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WO2013104877A1 - Améliorations apportées à une technologie d'application de revêtement - Google Patents

Améliorations apportées à une technologie d'application de revêtement Download PDF

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Publication number
WO2013104877A1
WO2013104877A1 PCT/GB2012/051599 GB2012051599W WO2013104877A1 WO 2013104877 A1 WO2013104877 A1 WO 2013104877A1 GB 2012051599 W GB2012051599 W GB 2012051599W WO 2013104877 A1 WO2013104877 A1 WO 2013104877A1
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WIPO (PCT)
Prior art keywords
unsubstituted
group
alkyl
substituted
platinum
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Application number
PCT/GB2012/051599
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English (en)
Inventor
Allan BERZINS
Alan Boardman
Original Assignee
Johnson Matthey Public Limited Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Johnson Matthey Public Limited Company filed Critical Johnson Matthey Public Limited Company
Priority to SG11201403144XA priority Critical patent/SG11201403144XA/en
Priority to EP12735613.7A priority patent/EP2802687A1/fr
Priority to CN201280066761.6A priority patent/CN104040032B/zh
Priority to US14/362,982 priority patent/US20150047984A1/en
Publication of WO2013104877A1 publication Critical patent/WO2013104877A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals
    • C25D3/52—Electroplating: Baths therefor from solutions of platinum group metals characterised by the organic bath constituents used

Definitions

  • the present invention concerns improvements in coating technology, more particularly it concerns improvements in the deposition of coatings of platinum by electroplating. Even more particularly, the present invention concerns improvements in the deposition of coatings of platinum by electroplating in a commercial or industrial process.
  • Electroplating is a well-known technique for applying coatings of platinum and other platinum group metals onto conductive substrates.
  • substrates for plating according to the present invention are conductive metals or graphite, composites incorporating conductive fibres or particles may be considered as well as plastics which have a keying metal deposit or flash coating.
  • the coatings may be a thin "flash" coating used for jewellery, or several microns in thickness, generally up to about 20 ⁇ , depending upon the intended use of the coated product; the coating may be thicker for certain applications.
  • P Salt is an ammoniacal solution of diammine dinitroplatinum(ll), i.e. (NH 3 ) 2 Pt(N0 2 )2- "Q salt ® " is an ammoniacal solution of tetraammineplatinum(ll) hydrogen orthophosphate.
  • EP0358375A has been very successfully used in industry. Plating is carried out at temperatures of 90°C or above. At such temperatures, water vapour and ammonia are driven off, with the consequential need to regularly replenish these components during plating in order to maintain plating rate. Additionally, the platinum salt needs to be replenished with use of the bath. There have been attempts to find alternatives to ammonia but there remains a need to find plating baths which are more environmentally friendly in reducing or eliminating the loss of toxic ammonia, and desirably which are less energy intensive and/or which offer other advantages, such as having a good plating rate, good coating properties and compatible with plating additives that improve coating properties.
  • the present invention relates to a platinum plating bath.
  • the bath may be used successfully over extended periods and the platinum component may be replenished easily.
  • the bath has good thermal stability in general and as such generally requires simple maintenance and analytical control.
  • the bath may also be used over a wide range of pHs and, in certain preferred embodiments, provide a safe, neutral non-corrosive bath.
  • the baths yield a bright and shiny plate.
  • the baths may be used under relatively energy-efficient conditions.
  • the baths have a good plating rate providing a good deposition of platinum in a reasonable period of time.
  • the baths may be used without the emission of ammonia or with only low emissions.
  • the present invention provides an aqueous platinum electroplating bath comprising: a) a source of platinum ions; and
  • the invention provides the use of the aqueous platinum electroplating bath of the present invention for plating platinum onto a substrate.
  • the point of attachment of a moiety or substituent is represented by For example, -OH is attached through the oxygen atom.
  • AlkyI refers to a straight-chain or branched saturated hydrocarbon group.
  • the alkyl group may have from 1 to 10 carbon atoms, in certain embodiments from 1 to 8 carbon atoms, in certain embodiments from 1 to 6 carbon atoms.
  • the alkyl group may be substituted or unsubstituted. Unless otherwise specified, the alkyl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable carbon atom.
  • Typical alkyl groups include but are not limited to methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n- pentyl, n-hexyl, and the like.
  • Alkenyl refers to a straight-chain or branched unsaturated hydrocarbon group having at least one carbon-carbon double bond. The group may be in either the cis- or trans- configuration around each double bond. In certain embodiments, the alkenyl group can have from 2 to 10 carbon atoms, in certain embodiments from 2 to 8 carbon atoms, in certain embodiments, 2 to 6 carbon atoms. The alkenyl group may be unsubstituted or substituted. Unless otherwise specified, the alkenyl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable carbon atom.
  • alkenyl groups include but are not limited to ethenyl (vinyl), 2-propenyl (allyl), 1- methylethenyl, 2-butenyl, 3-butenyl and the like.
  • Alkynyl refers to a straight-chain or branched unsaturated hydrocarbon group having at least one carbon-carbon triple bond. In certain embodiments, the alkynyl group can have from 2-10 carbon atoms, in certain embodiments from 2-8 carbon atoms, in certain embodiments, 2-6 carbon atoms. The alkynyl group may be unsubstituted or substituted.
  • alkynyl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable atom.
  • alkynyl groups include but are not limited to ethynyl, prop-1-ynyl, prop-2-ynyl, 1- methylprop-2-ynyl, but-1-ynyl, but-2-ynyl, but-3-ynyl and the like.
  • Aryl refers to an aromatic carbocyclic group.
  • the aryl group may have a single ring or multiple condensed rings. In certain embodiments, the aryl group can have from 6 to 20 carbon atoms, in certain embodiments from 6 to 15 carbon atoms, in certain embodiments, 6 to 12 carbon atoms.
  • the aryl group may be unsubstituted or substituted. Unless otherwise specified, the aryl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable carbon atom. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, anthracenyl and the like.
  • bath includes a concentrate for ease of storage and transport.
  • Borate ion refers to a range of ionic compounds containing boron and oxygen.
  • the borate ion may be a mononuclear species comprising a B0 3 or B0 4 unit, or a cyclic, linear, caged or polymeric structure formed by the linking together of B0 3 and/or B0 4 units by sharing oxygen atoms.
  • the term "borate ion” likewise includes metaborate ions, the chemical formula for which can be written in its simplest form as B0 2 . Metaborate ions, however, appear to exist as long chains of B0 3 units sharing two oxygen atoms. Examples of borate ions are provided below:
  • Cycloalkyl refers to a cyclic saturated hydrocarbon group.
  • the cycloalkyl group may have from 3-10 carbon atoms, in certain embodiments from 3-10 carbon atoms, in certain embodiments, 3-8 carbon atoms, in certain embodiments, 3-6 carbon atoms.
  • the cycloalkyl group may be unsubstituted or substituted. Unless otherwise specified, the cycloalkyl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable atom.
  • Typical cycloalkyl groups include but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.
  • Heterocycloalkyi refers to a saturated cyclic hydrocarbon group wherein one or more carbon atoms are independently replaced with one or more heteroatoms (e.g. nitrogen, oxygen, phosphorus and/or sulfur atoms).
  • the heterocycloalkyi group may have from 2-10 carbon atoms, in certain embodiments from 2-10 carbon atoms, in certain embodiments, 2-8 carbon atoms in certain embodiment, 2-6 carbon atoms.
  • the heterocycloalkyi group may be unsubstituted or substituted. Unless otherwise specified, the heterocycloalkyl group may be attached at any suitable atom and, if substituted, may be substituted at any suitable atom.
  • heterocycloalkyl group examples include but are not limited to epoxide, morpholinyl, piperadinyl, piperazinyl, thirranyl and the like.
  • Heteroalkyi refers to a straight-chain or branched saturated hydrocarbon group wherein one or more carbon atoms are independently replaced with one or more heteroatoms (e.g. nitrogen, oxygen, phosphorus and/or sulfur atoms).
  • the heteroalkyi group may have from 1 to 10 carbon atoms, in certain embodiments from 1 to 8 carbon atoms, in certain embodiments from 1 to 6 carbon atoms.
  • the heteroalkyi group may be unsubstituted or substituted. Unless otherwise specified, the heteroalkyi group may be attached at any suitable atom and, if substituted, may be substituted at any suitable atom.
  • Heteroaryl refers to an aromatic carbocyclic group wherein one or more carbon atoms are independently replaced with one or more heteroatoms (e.g. nitrogen, oxygen, phosphorus and/or sulfur atoms).
  • the heteroaryl group can have from 5 to 20 carbon atoms, in certain embodiments from 5 to 15 carbon atoms, in certain embodiments, 5 to 12 carbon atoms.
  • the heteroaryl group may be attached at any suitable atom and, if substituted, may be substituted at any suitable atom. Examples of heteroaryl groups include but are not limited to furanyl, indolyl, oxazolyl, pyridinyl, pyrimidinyl, thiazolyl, thiphenyl and the like.
  • Heteroatom refers to nitrogen, oxygen or sulfur, preferably nitrogen or oxygen and most preferably nitrogen.
  • Root temperature means from about 20°C to about 35°C.
  • Substituted refers to a group in which one or more (e.g. 1 , 2, 3, 4 or 5) hydrogen atoms are each independently replaced with substituents which may be the same or different.
  • the present invention provides an aqueous platinum electroplating bath comprising: a) a source of platinum ions; and
  • the source of platinum ions may be at least one (e.g. 1 , 2, 3, 4 or 5 preferably 1 ) platinum plating salt or complex.
  • the platinum plating salts useful in the invention include a large number of salts or dissolved complexes, for example, diammine dinitroplatinum(ll) (i.e. "P Salt"), tetraammineplatinum(ll) hydrogen orthophosphate (i.e.
  • tetraamineplatinum(ll) halides e.g. tetraamineplatinum(ll) chloride
  • alkali metal tetrahaloplatinates such as sodium tetrachloroplatinate(ll) or potassium tetrachloroplatinate
  • tetraamineplatinum(ll) hydrogen carbonate tetraammineplatinum(ll) hydroxide and tetraammineplatinum(ll) nitrate.
  • the platinum ions may be cationic or anionic.
  • the platinum ions may be may be at an oxidation state of (II) or (IV).
  • the bath of the present invention comprises borate ions.
  • the source of borate ions is a boron-containing acid optionally in combination with at least one borate salt.
  • suitable boron-containing acids include but are not limited to boric acid, tetraboric acid and pyroboric acid.
  • the source of borate ions is a boron-containing acid, preferably boric acid.
  • the source of borate ions is a boron-containing acid (preferably boric acid) and at least one (e.g. 1 , 2, 3, 4 or 5) borate salt.
  • the use of a boron-containing acid in combination with one or more borate salts may be desirable as a buffered plating bath may be prepared.
  • Polymers also appear to be present in mixed solutions of boric acid and borates e.g.: 2B(OH) 3 + B(OH) 4 - B 3 0 3 (OH) 4 - + 3H 2 0
  • the at least one borate salt may be selected from the group consisting of alkali metal borates, alkaline earth metal borates and ammonium borates. Hydrates or anhydrous salts may be used, although the use of anhydrous salts is not essential as the plating bath is aqueous.
  • the salt is an alkali metal salt
  • the salt is preferably a lithium, sodium or potassium salt.
  • the salt is preferably a magnesium or calcium salt.
  • borate salts include but are not limited to metaborates, tetraborates, biborates and pentaborates, such as lithium metaborate (LiB0 2 ), lithium metaborate dihydrate (LiB0 2 .2H 2 0), sodium metaborate (NaB0 2 ), sodium metaborate hydrate (NaB0 2 .xH 2 0), calcium metaborate [Ca(B0 2 ) 2 ], calcium metaborate dihydrate [Ca(B0 2 ) 2 .2H 2 0], sodium tetraborate (Na 4 B 4 0 7 ), sodium tetraborate decahydrate (Na 4 B4O 7 .10H 2 O), potassium tetraborate (K4B4O7) , potassium tetraborate tetrahydrate (K4B 4 07.4H 2 0), ammonium biborate [(NH 4 ) 2 B 4 0 7 ], ammonium biborate tetrahydrate [(NH
  • the source of borate ions may be a metaborate salt optionally in combination with at least one other borate salt.
  • the source of borate ions is a metaborate salt, such as an alkali metal (e.g. sodium or potassium), alkaline earth metal (e.g. calcium) or ammonium metaborate.
  • the source of borate ions is a metaborate salt in combination with at least one (e.g. 1 , 2, 3, 4 or 5) other borate salt. Suitable metaborate and borate salts are as given above.
  • the plating baths when made up to be ready for use suitably have a borate ion concentration of about 0.1 to about 90 g/litre.
  • the borate ion concentration is about >0.1 g/litre. In some embodiments, the borate ion concentration is about >1 g/litre. In some embodiments, the borate ion concentration is about >2.5 g/litre. In some embodiments, the borate ion concentration is about >5 g/litre. In some embodiments, the borate ion concentration is about >10 g/litre.
  • the borate ion concentration is about ⁇ 85 g/litre, in some embodiments about ⁇ 80 g/litre, in some embodiments about ⁇ 75 g/litre, in some embodiments about ⁇ 70 g/litre, in some embodiments about ⁇ 65 g/litre, in some embodiments about ⁇ 60 g/litre, in some embodiments about ⁇ 55 g/litre, in some embodiments about ⁇ 50 g/litre, in some embodiments about ⁇ 45 g/litre, in some embodiments about ⁇ 40 g/litre, in some embodiments about ⁇ 35 g/litre, in some embodiments about ⁇ 30 g/litre, in some embodiments about ⁇ 25 g/litre, in some embodiments about ⁇ 20 g/litre.
  • the borate ion concentration is about 5 to about 30 g/litre.
  • the borate ion concentration may be determined from the mass of the components used to make up the bath. However, when the bath is in use, the borate ion concentration may be assessed using analytical techniques such as titration, gravimetric methods or ion-chromatography.
  • the platinum plating bath when it is ready for use or in use has a pH in the range from about 2 to about 14. If the pH of the bath is ⁇ 2, the bath may be very corrosive which may present equipment problems with its use and containment. For example, the equipment needed to analyse the bath (e.g. HPLC internals and column) may be severely affected, or levellers (if used) or other organic additives (if used), such as wetting agents may be destroyed. Moreover, the range of substrates which may be plated would be limited, as well as the materials used in supporting the workpiece.
  • the pH is >2, in certain embodiments >2.5, in certain embodiments >3, in certain embodiments >3.5, in certain embodiments >4, in certain embodiments >4.5, in certain embodiments >5, in certain embodiments >5.5, in certain embodiments >6, in certain embodiments >6.5, in certain embodiments >7, in certain embodiments >7.5.
  • the pH is ⁇ 14, in certain embodiments ⁇ 13.5, in certain embodiments ⁇ 13, in certain embodiments ⁇ 12.5, in certain embodiments ⁇ 12, in certain embodiments ⁇ 1 1.5, in certain embodiments ⁇ 1 1 , in certain embodiments ⁇ 10.5, in certain embodiments ⁇ 10, in certain embodiments ⁇ 9.5, in certain embodiments ⁇ 9, in certain embodiments ⁇ 8.5, in certain embodiments ⁇ 8.
  • the pH is from about 6 to about 9.
  • a bath having a pH of from about 7 to about 9 may be termed a "neutral" bath and is an example of a non-corrosive plating bath.
  • a neutral bath may be desirable as there is little bubbling at the cathode as most energy is used in plating.
  • the pH is from about 2 to about 7.
  • a bath having a pH of from about 2 to about 7 may be termed an "acid" bath.
  • An acid bath may be desirable as the surface to be plated is less likely to be oxidised and because of this, adhesion of the applied electroplate can be improved.
  • the pH of the plating bath may be adjusted by the addition of suitable acids, bases or a mixture thereof.
  • suitable acids for example, "Q Salt ® " solution is normally supplied for use at about pH 10 to 1 1 and the addition of acid is required to lower the pH of the solution.
  • Any suitable inorganic acid, organic acid or mixture thereof may be utilised. Examples of suitable organic acids include but are not limited to formic acid, acetic acid and oxalic acid.
  • suitable inorganic acids include but are not limited to hydrohalic acids (e.g. HCI, HBr or HI), sulfur-containing acids (e.g. sulphuric acid), phosphorus-containing acids (such as hypophosphoric acid (H 3 P0 2 ), phosphorous acid (H 3 P0 3 ), ortho-phosphoric acid (H 3 P0 4 )) and boron-containing acids.
  • hydrohalic acids e.g. HCI, HBr or HI
  • sulfur-containing acids e.g. sulphuric acid
  • phosphorus-containing acids such as hypophosphoric acid (H 3 P0 2 ), phosphorous acid (H 3 P0 3 ), ortho-phosphoric acid (H 3 P0 4 )
  • boron-containing acids boron-containing acids.
  • any suitable inorganic base, organic base or mixture may be utilised to increase the pH of the plating bath, if this is required.
  • suitable inorganic bases include but are not limited to alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkali metal phosphates and alkali metal silicates, such as potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium phosphate, sodium silicate, potassium silicate.
  • suitable organic bases include but are not limited to amines and tetraalkyi ammonium hydroxides, such as ammonia, ethanolamine or choline hydroxide.
  • the borate salt itself may act as a base.
  • the pH will change slowly as the platinum is plated from the bath.
  • the concentration of the platinum can be maintained in the bath by adding fresh plating solution that comprises the platinum ions, borate ions, acid (if used) and base (if used). Alternatively, each component may be added individually. Desirably, the plating bath is analysed regularly and replenished as necessary in order to maintain the desired concentration of each component. Suitable concentrations for e.g. the platinum ions and/or borate ions when the bath is in use are generally those provided above and below in respect of when the bath is ready for use.
  • the platinum ions and the borate ions may be obtained from different sources.
  • the platinum ions may be derived from the platinum plating salts and complexes
  • the borate ions may be derived from a boron-containing acid optionally in combination with one or more borate salts or, a metaborate salt optionally in combination with one or more other metaborate salts.
  • the source of platinum ions and the source of borate ions may be obtained from the same source.
  • the source for both may be a platinum borate salt or complex.
  • the use of sulfur-containing materials may not be desirable.
  • An example where sulfur-containing materials may not be desirable is the platinum plating of materials for aerospace applications, especially turbine blades. Accordingly, plating baths containing materials such as sulfur-containing platinum plating salts or complexes, or sulfur- containing acids may not be optimal for such applications.
  • the aqueous platinum plating bath does not comprise a sulfur-containing platinum plating salt or complex.
  • the aqueous platinum plating bath does not comprise a sulfur-containing acid (if used).
  • sulfur-containing materials may be suitable for the platinum plating of materials other than for aerospace applications.
  • halogen-containing materials particularly chlorine-containing materials
  • the plating baths when made up to be ready for use suitably have a platinum ion concentration of about 1 to about 30 g/litre. Preferred platinum concentrations depend upon the product to be coated and the coating apparatus but are typically about 5 g/litre to about 20 g/litre for most normal operations. In some embodiments, the platinum ion concentration is >5 g/litre, for example, >7 g/litre. In some embodiments, the platinum ion concentration is >10 g/litre, for example, >15 g/litre. In some embodiments, the platinum ion concentration is ⁇ 20 g/litre, for example, ⁇ 15 g/litre.
  • the plating bath of the present invention may be used at temperatures from about room temperature to about 100°C.
  • the temperature may be from about 60°C to about 100°C, in certain embodiments from about 60°C to about 95°C, in certain embodiments from about 70°C to about 95°C, in certain embodiments from about 75°C to about 95°C, in certain embodiments from about 75°C to about 90°C, in certain embodiments from about 70°C to about 90°C.
  • the higher the plating temperature the greater the plating rate. Greater loss of water by evaporation at higher temperatures may occur, however, this may be monitored and adjusted as appropriate through the addition of water to the bath.
  • the bath of the invention may be used successfully under broadly conventional conditions and current densities.
  • the current density may be from about 1 to about 25mA cm 2 , for example, from about 2 to about 10 mA/cm 2 , such as from about 2 to about 6 mA/cm 2 , e.g. about 4 mA/cm 2 .
  • the bath can be used to plate using complex methods such as pulse plating or impressed AC or other interrupted plating techniques, but direct current electroplating is preferred.
  • the aqueous platinum electroplating bath is suitable for use in an industrial or commercial electroplating process.
  • the bath of the present invention may be used to rapidly coat large substrates in an industrial sized tank in a continual process rather than being restricted to a research tool explored by cyclic voltammetry, or by other electrochemical probing techniques in a small cell, whilst confined to a small cell.
  • the rate at which the platinum is plated out of solution should be such that the process is commercially viable. In one embodiment, therefore, the rate of plating is about >0.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >1 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >1.5 microns thickness of platinum per hour.
  • the rate of plating is about >2 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >2.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >3 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >3.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >4 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >4 .5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >5 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >5.5 microns thickness of platinum per hour.
  • the rate of plating is about >6 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >6.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >7 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >7.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >8 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >8.5 microns thickness of platinum per hour. In another embodiment, the rate of plating is about >9 microns thickness of platinum per hour. In yet another embodiment, the rate of plating is about >9.5 microns thickness of platinum per hour.
  • the rate of plating is about >10 microns thickness of platinum per hour. In one preferred embodiment, the rate of plating is from about 5 microns thickness of platinum per hour to about 10 microns thickness per hour.
  • the plating bath comprises one or more other plating salts or complexes (which are not platinum plating salts or complexes)
  • the above embodiments relate to the plating rate and thickness of platinum alloy per hour.
  • the platinum electroplating bath of the present invention therefore may further comprise at least one leveller.
  • the leveller may contribute to the production of a bright or shiny plate.
  • the leveller may contribute to the lustre of the produced plate.
  • the leveller may help to generate a plate with increased hardness.
  • the leveller comprises at least one unsaturated carbon-carbon or unsaturated carbon-heteroatom bond.
  • the leveller is selected from the group consisting of at least one:
  • the leveller may be a substituted or unsubstituted saccharine or salt thereof.
  • the leveller is a compound of formula (1 ) or salts thereof:
  • each R-i is independently an unsubstituted C1-C10 alkyl group
  • R 2 is selected from the group consisting of H, unsubstituted C1-C10 alkyl, an alkali metal ion and an alkaline earth metal ion.
  • m is 0 i.e. the aryl group is unsubstituted.
  • R 2 is H.
  • the compound of formula (1 ) is a salt wherein R 2 is an alkali metal cation or an alkaline earth metal cation e.g. Na + , K + or Ca 2+ .
  • Examples of compounds of formula (1 ) include but are not limited to saccharine, sodium saccharine, potassium saccharine and calcium saccharine.
  • the anionic sulfobenzimide group may be present as an amido tautomer (for example see the structure of calcium saccharine above) and/or as the iminyl tautomer (for example see the structure of sodium and potassium saccharine above).
  • the amido and iminyl tautomers are included within the definition of the compound of formula (1 ).
  • the benzopyranone may be a substituted or unsubstituted 1-benzopyran-2-one, 2-benzopyran-1-one or 1-benzopyran-4-one.
  • the leveller is a compound of formula (2a), (2b) or (2c):
  • p 0, 1 or 2;
  • each R 10 and n is independently selected from an unsubstituted C1-C10 alkyl group.
  • the leveller is a compound of formula (2a). In another embodiment, the leveller is a compound of formula (2b). In yet another embodiment, the leveller is a compound of formula (2c).
  • n is 0 i.e. the aryl group is unsubstituted.
  • p is 0.
  • An example of a compound of formula (2a) includes but is not limited to coumarin.
  • the leveller may be a substituted or unsubstituted benzaldehyde or derivative thereof.
  • the leveller is a compound of formula (3a) or (3b):
  • R 2 o is selected from the group consisting of H and -OR23 ;
  • R21 and R 2 2 are independently selected from the group consisting of H, -C(0)R 2 4 and unsubstituted Ci-Ci 0 -alkyl;
  • R23 and R 2 4 are independently selected from the group consisting of H and unsubstituted Ci-Ci 0 -alkyl.
  • the leveller is a compound of formula (3a). In another embodiment, the leveller is a compound of formula (3b).
  • R 2 o is selected from the group consisting of H, -OH, -OMe, -OEt, -OPr (n- or i-) and -OBu (n-, i- or t-) and more preferably, H, -OH and -OMe.
  • R 2 3 is preferably -H, - Me, -Et, -Pr (n- or i-), -Bu (n-, i- or t-) and more preferably -H or -OMe.
  • each R 2 i and R 22 is independently selected from the group consisting of H, methyl, ethyl, propyl (n- or i-), butyl (n-, i- or t-), -C(0)H, -COMe, -COEt, -COPr (n- or i-) and -COBu (n-, i- or t-). More preferably, each R 21 and R 22 is independently selected from the group consisting of H, methyl, ethyl and -COMe. In these cases, R 24 is preferably H, methyl, ethyl, propyl (n- or i-), butyl (n-, i- or t-) and more preferably Me.
  • Examples of compounds of formula (3a) include but are not limited to vanillin, ethyl vanillin, vanillin acetate, vanillic acid and methyl vallinate.
  • Examples of compounds of formula (3b) include but are not limited to ortho-vanillin and 3-methoxysalicylic acid.
  • the leveller may be a substituted or unsubstituted alkene. In this instance, it is preferred that the leveller is not ethylene. In one preferred embodiment, the leveller is a compound of formula (4):
  • each R 30 , R31 , R32 and R 33 is independently selected from the group consisting of H, unsubstituted Ci-Ci 0 -alkyl, substituted Ci-Ci 0 -alkyl, -C0 2 R 34 , -NR34R35, -CONR34R35 and -CN, provided that R 30 , R31 , R32 and R 33 are not all H,
  • substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) - OH, -CO2R36, -OC(0)R 36 , -NR 36 R 3 7, -CONR 36 R 3 7, -CN, -S0 3 " Na + and -S0 3 " K + ;
  • R 34 and R 35 are independently selected from the group consisting of H and unsubstituted Ci-Ci 0 -alkyl;
  • R 36 and R 37 are independently selected from the group consisting of H and unsubstituted Ci-Ci 0 -alkyl.
  • the compounds of formula (4) may be cis-, trans- or geminal-alkenyl compounds.
  • R 30 and R 32 or R 31 and R 33 are H.
  • R 30 and R 33 or R 31 and R 32 are H.
  • R 30 and R 31 or R 32 and R 33 are H.
  • R 30 , R31 , R32 and R 33 may each be substituted with a group other than H.
  • each R 30 , R31 , R32 and R 33 is independently selected from the group consisting of H, unsubstituted Ci-Ci 0 -alkyl, substituted Ci-Ci 0 -alkyl, -NH 2 and -CN.
  • the substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) -OH, -OC(0)Me, -NH 2 , -CN and -S0 3 " Na + and -S0 3 " K + .
  • each R 30 , R31 , R32 and R 33 is independently selected from the group consisting of H, -CH 2 -OH, -CH(OH)CH 2 -OH, -NH 2 and -CN.
  • Examples of compounds of formula (4) include but are not limited to butenediol (e.g. trans-1 ,4-butenediol, cis-2-butene-1 ,4-diol, or 3-butene-1 ,2-diol) and diaminomaleonitrile.
  • the leveller may be a water-soluble substituted or unsubstituted C 2 -Ci 0 -alkyne provided the alkyne is not acetylene.
  • the leveller is a compound of formula (5):
  • R 40 and R 41 are independently selected from the group consisting of H, unsubstituted C 1 -C 10 - alkyl and substituted Ci-Ci 0 -alkyl, provided that R 40 and R 41 are not both H, wherein the substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) of -
  • R 42 and R 43 are independently selected from the group consisting of H and unsubstituted Ci-Ci 0 -alkyl.
  • R 40 and R 41 are independently selected from the group consisting of H, unsubstituted d- C-io-alkyl and substituted Ci-Ci 0 -alkyl, wherein the substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) of -OH, OC(0)Me, -NH 2 , -CN, -S0 3 ⁇ Na + and -S0 3 ⁇ K + . More preferably, R 40 and R 41 are independently selected from the group consisting of H, -CH 2 -OH, - CH(OH)CH 2 -OH and -CH 2 OC(0)Me. Examples of compounds of formula (5) include but are not limited to 1 ,4-butynediol, 1 ,4-butynediol diacetate and propargyl alcohol.
  • the leveller is a substituted or unsubstituted alkylnitrile, it is preferred that the leveller is a compound of formula (6):
  • R 50 is a substituted or unsubstituted Ci-Ci 0 -alkyl, and the substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) of -OR 51 , -CO2R51 , -OC(0)R 5 i, -NR 51 R 52 and -CN; and
  • R 51 and R 52 are independently selected from the group consisting of H and unsubstituted d- C-io-alkyl.
  • R 50 is a substituted or unsubstituted Ci-Ci 0 -alkyl, wherein the substituents are selected from the group consisting of at least one (e.g. 1 , 2, 3, 4 or 5) of -OH, -OMe, -OPr (n- or i-), -OBu (n-, i- or t-), -C0 2 H, -NH 2 and -CN.
  • R 50 is selected from the group consisting of -CH 2 CH 2 - OH, -CH(OH)-CH 3 , -CH2CO2H and -CH 2 -CH 2 -CN.
  • Examples of compounds of formula (6) include but are not limited to 3-hydroxypropionitrile, 2-hydroxypropionitrile, cyanoacetic acid and succinonitrile
  • the leveller may be a substituted or unsubstituted pyridine or an addition salt thereof.
  • the leveller is a compound of formula (7a), (7b) or (7c):
  • R 62 is selected from the group consisting of H, -OH and unsubstituted Ci-Ci 0 -alkyl;
  • R 63 is selected from the group consisting of H, -OH, unsubstituted Ci-Ci 0 -alkyl, unsubstituted Ci-Ci 0 - alkyl-C0 2 H, -NH 2 , -NH(unsubstituted d-C ⁇ -alkyl), -N(unsubstituted d-C ⁇ -alkyl ⁇ ;
  • R 64 is selected from the groups defined for R 62 ;
  • R 65 is selected from the groups defined for R 63 ;
  • each x is 0, 1 , 2 or 3;
  • each y is 0, 1 , 2, 3 or 4.
  • the leveller is a compound of formula (7a). In another embodiment, the leveller is a compound of (7b). In yet another embodiment, the leveller is a compound of (7c).
  • the compound of formula (7a) is unsubstituted i.e. x is 0.
  • x is 1 i.e. the compound (7a) is monosubstituted.
  • the substituent R 60 may be attached to any one of the carbons in the pyridine ring i.e. at C-2, C-3 or C-4.
  • x is 2 for the compound of (7a) i.e. the compound is disubstituted.
  • each substituent R 60 may be the same or different.
  • the substituents may be attached to any of the carbons in the pyridine ring i.e.
  • the compound (7a) may be 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5- or 3,6-disubstituted.
  • compound (7a) is trisubstituted i.e x is 3.
  • each substituent R 60 may be the same or different.
  • the substituents may be attached to any of the carbons in the pyridine ring i.e. the compound (7a) may be 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6-, 3,4,5- or 3,4,6-trisubstituted.
  • x may be 0, 1 , 2 or 3 for the compound of formula (7b).
  • the pyridinyl ring is unsubstituted.
  • the R 60 substituent may be attached at any of the carbon atoms at C-2, C-3 or C-4.
  • each R 60 substituent may be the same or different.
  • the substituents may be attached to any of the carbons in the pyridine ring i.e. the compound (7b) may be 2,3-, 2,4- or 3,4-substituted.
  • x is 3 and each R 60 is attached at C-2, C-3 and C-4. In this instance, each substituent R 60 may be the same or different.
  • y may be 0, 1 , 2, 3 or 4 for the compound (7b). In one embodiment, y is 0. In yet another embodiment, y is 1. In this instance, the substituent R 61 may be attached to any of the carbon atoms at C-5, C-6, C-7 or C-8. In yet another embodiment, when y is 2, each R 61 substituent may be the same or different. The substituents may be attached in any substitution pattern to any of the carbons at C-5, C-6, C-7 or C-8 i.e. the compound (7b) may be 5,6-, 5,7-, 5,8-, 6,7-, 6,8- or 7,8- substituted. In another embodiment, when y is 3, each R 61 substituent may be the same or different.
  • the substituents may be attached in any combination to the carbons at C-5, C-6, C-7 or C-8 i.e. the compound (7b) may be 5,6,7-, 5,6,8-, 5,7,8- or 6,7,8-substituted.
  • y is 4 and each R 61 is attached at C-5, C-6, C-7 and C-8. In this instance, each substituent R 61 may be the same or different.
  • x and y are 0 i.e. compound (7b) is quinoline.
  • x may be 0, 1 , 2 or 3 for the compound of formula (7c).
  • the pyridinyl ring is unsubstituted.
  • the R 60 substituent may be attached at any of the carbon atoms at C-1 , C-3 or C-4.
  • each R 60 substituent may be the same or different.
  • the substituents may be attached to any of the carbons in the pyridine ring i.e. the compound (7c) may be 1 ,3-, 1 ,4- or 3,4-substituted.
  • x is 3 and each R 60 is attached at C-1 , C-3 and C-4. In this instance, each substituent R 60 may be the same or different.
  • y may be 0, 1 , 2, 3 or 4 for the compound (7c). In one embodiment, y is 0. In yet another embodiment, y is 1. In this instance, the substituent R 61 may be attached to any of the carbon atoms at C-5, C-6, C-7 or C-8. In yet another embodiment, when y is 2, each R 61 substituent may be the same or different. The substituents may be attached in any combination to any of the carbons at C-5, C-6, C-7 or C-8 i.e. the compound (7c) may be 5,6-, 5,7-, 5,8-, 6,7-, 6,8- or 7,8- substituted. In another embodiment, when y is 3, each R 61 substituent may be the same or different.
  • the substituents may be attached in any combination to the carbons at C-5, C-6, C-7 or C-8 i.e. the compound (7c) may be 5,6,7-, 5,6,8-, 5,7,8- or 6,7,8-substituted.
  • y is 4 and each R 61 is attached at C-5, C-6, C-7 and C-8. In this instance, each substituent R 61 may be the same or different.
  • x and y is 0 i.e. compound (7c) is isoquinoline.
  • the substituents are selected from the group consisting of at least one (e.g.
  • R 62 and R 64 are preferably independently selected from the group consisting of H, -OH, methyl, ethyl, propyl (n-or i-) and butyl (n-, i- or t-).
  • R 63 and R 65 are preferably independently selected from the group consisting of H, -OH, methyl, ethyl, propyl (n-or i-), butyl (n-, i- or t-), -NH 2 , -NHMe, - NHEt, -NHPr (n- or i-), -NHBu (n-, i- or t-), -NMe 2 , -NEt 2 , -NPr 2 (wherein each Pr group is independently n- or i-), -NBu 2 (wherein each Bu group is independently n-, i- or t-) and -CH 2 -C0 2 H.
  • R 61 is selected from the group consisting of methyl, ethyl, propyl (n-or i-), butyl (n-, i- or t-), -CN, -C0 2 H, -COH, -CONH(OH), -CONH(NH 2 ), - CONH 2 , -C0 2 Me, -CONMe 2 , -C0 2 Et, -CONEt 2 , -CONMeEt, -C(NOH)(NH 2 ), -C(NOH)(NMe 2 ), C(NOH)(NEt 2 ), and -C(NOH)(NMeEt).
  • Examples of compounds of formula (7a), (7b) and (7c) include but are not limited to 4-cyanopyridine, 2-cyanopyridine, nicotinic hydrazide, iso-nicotinamide, nicotinamide, iso-nicotinic acid, nicotinic acid, nicotine, methyl nicotinate, ⁇ , ⁇ -dimethylnicotinamide, trans-3-(3-pyridyl)acrylic acid, trans-3-(4- pyridyl)acrylic acid, pyridine-3-sulfonic acid, 4-(2-pyridylazo)resorcinol, iso-nicotinaldehyde, nicotinaldehyde, bipyridyl (2,2 - and 4,4'-), quinoline, isoquinoline or other compound of formula (7a), (7b) or (7c) illustrated below.
  • C-2 Methylpicolinate C-2: ⁇ , ⁇ -Dimethyl picolinamide C-2: ⁇ , ⁇ -Diethyl picolinamide C-3: Methyl nicotinate C-3: ⁇ , ⁇ -Dimethyl nicotinamide C-3: ⁇ , ⁇ -Diethyl nicotinamide C-4: Methyl isonicotinate C-4: ⁇ , ⁇ -Dimethyl isonicotinamide C-4: ⁇ , ⁇ -Diethyl isonicotinamide
  • C-2 Pyridine-2-sulfonic acid
  • C-2 4-(2-Pyridylazo)resorci nol
  • C-2 Picolinaldehyde
  • C-3 Pyridine-3-sulfonic acid
  • C-3 4-(3-Pyridylazo)resorci nol
  • C-4 Pyridine-4-sulfonic acid
  • C-4 4-(2-Pyridylazo)resorci nol C-4: Isonicotinaldehyde
  • C-2 2-Pyridylacetic acid
  • C-2 2-Pyridylpropionic acid
  • C-2 2-Pyridylacetonitrile
  • C-4 4-Pyridylacetic acid
  • C-4 4-Pyridylpropionic acid
  • C-4 4-Pyridylacetonitrile
  • a compound of formula (7) can convert to another compound of formula (7) under the conditions used in the plating bath of the present invention, i.e such as one compound of formula (7a) to another compound of formula (7a), a compound (7b) to another compound (7b) or a compound (7c) to another compound (7c).
  • 4-cyanopyridine, iso-nicotinamide and iso-nicotinaldehyde may each convert to iso-nicotinic acid
  • 3-cyanopyridine, nicotinamide, nicotinaldehyde and nicotinic hydrazide may each convert to nicotinic acid.
  • the compound of formula (7) therefore includes within its scope the starting compound of formula (7), the converted compound of formula (7) and mixtures thereof. In this embodiment, it is not envisaged that e.g. a compound (7a) would convert to e.g. a compound (7c) or vice versa.
  • the salt may be an alkali metal salt, an alkaline earth metal salt or an ammonium salt.
  • the salt is a sodium, potassium, calcium or ammonium salt.
  • Examples of salts of compound of formula (7a), (7b) or (7c) include but are not limited to nicotinic acid sodium salt, nicotinic acid potassium salt, nicotinic acid calcium salt, nicotinic acid ammonium salt, iso-nicotinic acid sodium salt, iso-nicotinic acid potassium salt, iso-nicotinic acid calcium salt and iso-nicotinic acid ammonium salt.
  • the triazole may be a 1 ,2,3- or a 1 ,2,4- triazole.
  • the leveller is a compound of formula (8):
  • R 70 is selected from a group consisting of H, -CO2R72 and -NR72R73;
  • R 71 is selected from a group consisting of H and unsubstituted Ci-Ci 0 -alkyl
  • R 72 and R 73 are independently selected from the group consisting of H and unsubstituted Ci-Ci 0 -alkyl; one of X-i and X 2 is C-R 74 and the other of X-i and X 2 is N; and
  • R 74 is selected from a group as defined for R 70 .
  • X-i is C-R 74 and X 2 is N. In another embodiment, X 2 is C-R 74 and X-i is N.
  • R 70 is selected from a group consisting of H, -C0 2 H, -C0 2 Me, -C0 2 Et, -C0 2 Pr (n- or i-), - C0 2 Bu (n-, i- or t-), -NH 2 , -NHMe, -NHEt, -NHPr (n- or i-), -NHBu (n-, i- or t-), -NMe 2 , -NEt 2 , -NPr 2 (wherein each Pr group is independently n- or i-) and -NBu 2 (wherein each Bu group is independently n-, i- or t-).
  • R 72 and R 73 therefore are independently selected from the group consisting of H, methyl, ethyl, propyl (n-or i-) and butyl (n-, i- or t-).
  • R 71 is preferably selected from a group consisting of H, methyl, ethyl, propyl (n-or i-) and butyl (n-, i- or t-).
  • R 74 is preferably selected from the group consisting of H, -C0 2 H, -C0 2 Me, -C0 2 Et, -C0 2 Pr (n- or i-), -C0 2 Bu (n-, i- or t-), -NH 2 , -NHMe, -NHEt, - NHPr (n- or i-), -NHBu (n-, i- or t-), -NMe 2 , -NEt 2 , -NPr 2 (wherein each Pr group is independently n- or i-) and -NBu 2 (wherein each Bu group is independently n-, i- or t-).
  • Examples of compounds of formula (8) include but are not limited to 3-amino-1 ,2,4-triazole and 3-amino-1 ,2,4-triazole-5- carboxylic acid.
  • the leveller may be a substituted or unsubstituted pyridinium salt.
  • the leveller is a compound of formula (9a), (9b) or (9c):
  • R 62 is selected from the group consisting of H, -OH and unsubstituted Ci-Ci 0 -alkyl;
  • R 63 is selected from the group consisting of H, -OH, unsubstituted Ci-Ci 0 -alkyl, unsubstituted Ci-Ci 0 - alkyl-C0 2 H, -NH 2 , -NH(unsubstituted d-C ⁇ -alkyl), -N(unsubstituted d-C ⁇ -alkyl ⁇ ;
  • R 64 is selected from the groups defined for R 62 ;
  • R 65 is selected from the groups defined for R 63 ;
  • R 82 is selected from the group consisting of -O " and unsubstituted Ci-Ci 0 -alkyl;
  • Z is a counterion when R 82 is an unsubstituted Ci-Ci 0 -alkyl
  • each x is 0, 1 , 2 or 3;
  • each y is 0, 1 , 2, 3 or 4.
  • the leveller is a compound of formula (9a). In another embodiment, the leveller is a compound of formula (9b). In yet another embodiment, the leveller is a compound of formula (9c).
  • the various embodiments for R 60 , Rei , R62, R63, R64, R65, x and y are as generally described above with regard to the compounds of formulae (7a), (7b) and (7c) and each of these embodiments can be considered recited herein with regard to the compounds of formulae (9a), (9b) and (9c).
  • R 82 is a substituent attached to the nitrogen atom.
  • R 82 may be -O " i.e. the compound of formula (9a), (9b) or (9c) is an N-oxide.
  • a counterion Z is generally not required in order to stabilise the pyridinyl N atom.
  • R 82 may be an unsubstituted Ci-Ci 0 -alkyl, such as methyl, ethyl, propyl (n-or i-), butyl (n-, i- or t-).
  • a counterion Z is required and any suitable counterion may be utilised, for example, halide anions such as F “ , CI “ , Br “ or I " .
  • a compound of formula (9) it is possible for a compound of formula (9) to convert to another compound of formula (9) under the conditions used in the plating bath of the present invention, i.e such as one compound of formula (9a) to another compound of formula (9a), a compound (9b) to another compound (9b) or a compound (9c) to another compound (9c).
  • the compound of formula (9) therefore includes within its scope the starting compound of formula (9), the converted compound of formula (9) and mixtures thereof. In this embodiment, it is not envisaged that e.g. a compound (9a) would convert to e.g. a compound (9c) or vice versa.
  • Examples of compounds of formula (9a), (9b) and (9c) include but are not limited to those illustrated below:
  • C-3 Nicotinic acid N-oxide
  • C-3 Nicotinamide N-oxide
  • the leveller may be a substituted or unsubstituted polyalkyleneimine.
  • the leveller is preferably unsubstituted polyethyleneimine or ethoxylated polyethyleneimine.
  • the leveller Before the bath is utilised in a plating process, the leveller may in insoluble, partially soluble or substantially completely soluble in the other bath components. However, when the bath is in use it is desirable that the leveller is substantially completely soluble at the desired plating temperature.
  • the leveller may be added in any suitable concentration, for example, from about 0.0001 g/litre to about 10 g/litre.
  • the concentration of leveller is about >0.001 g/litre, in another embodiment about >0.01 g/litre, in another embodiment about >0.1 g/litre.
  • the concentration of leveller is about ⁇ 9 g/litre, in another embodiment about ⁇ 8 g/litre, in another embodiment about ⁇ 7 g/litre, in another embodiment about ⁇ 6 g/litre, in another embodiment about ⁇ 5 g/litre.
  • the concentration of the leveller is about 0.01 g/litre to about 5 g/litre.
  • the aqueous platinum electroplating bath may comprise more than one leveller e.g. 2, 3, 4, or 5 levellers. In this instance, each leveller may be independently selected from those as described above.
  • the plating bath of the present invention may comprise one or more other plating salts or complexes, such as platinum group metal (PGM) plating salts or complexes, or base metal plating salts or complexes.
  • PGM platinum group metal
  • the PGM salts or complexes may be rhodium, palladium, iridium, ruthenium or rhenium plating salts or complexes, such as HRe0 4 .
  • Base metal plating salts include but are not limited to hexaamminenickel(ll) chloride.
  • the bath may be prepared by adding the components in any suitable order, for example, in one method an acid (if used) may be added to an aqueous solution of the platinum ions, followed by the borate ion source, base (if used), leveller (if used) and other components (if used). In another method, a base may be added to an aqueous solution of a platinum borate salt, followed by a leveller (if used) and other components (if used).
  • the plating baths may further comprise one or more brighteners or other components, for example, surfactants or wetting agents to suppress bubble formation on the substrate.
  • Suitable wetting agents/surfactants include polyethyleneglycol 50% aqueous solution or long chain alkyl sarcosines.
  • the invention includes a method of plating a PGM onto a substrate, comprising electroplating using the bath of the invention.
  • the substrate is preferably a conductive substrate, such as a metal, conductive plastic or conductive ceramic.
  • the invention includes the use of an aqueous platinum plating bath as defined herein for plating platinum or platinum alloy onto a substrate.
  • platinum is plated onto a substrate.
  • a platinum alloy is plated onto a substrate.
  • the substrate may be a metal (e.g. a metal article or metal powder), conductive plastic or conductive ceramic (such as a zirconia oxygen sensor or ceramic ozone destructor for motor vehicles or aircraft).
  • Figure 1 illustrates a shaped part of the given dimensions which is used to assess the deposition of platinum (or platinum alloys) onto shaped parts.
  • 20Q "Q salt ®” material is commercially available from Johnson Matthey and is an ammoniacal solution of tetraammineplatinum(ll) hydrogen phosphate at a pH of about 10 to 1 1 and 20 g/l Pt.
  • substrates were 9 x 2.5 cm panels, thickness 1 mm for 316 stainless steel and 2 mm for brass.
  • the brass panels were either manually polished using "Brasso ® " or grit blasted using Type 150 and 180/220 brown aerospace grade grit; stainless steel panels were cleaned and degreased using 1 M sodium hydroxide solution, followed by a dip in 6M hydrochloric acid. The panels were immersed in the plating baths to a depth of 5 cm, within 150, 400 or 600 ml glass beakers.
  • the shaped substrates as shown in Figure 1 were of lconel or 316 stainless steel and were treated before use by grit blasting with 180/220 brown aerospace grit and alkali cleaning using 1 M sodium hydroxide solution for 6 minutes at a temperature of at least 60°C, followed by a dip (1-2 minutes) in 6M hydrochloric acid at room temperature. The substrates were washed thoroughly between each treatment.
  • each bath comprised approx. 300ml of plating solution was heated to 90°C in a 400 ml beaker containing a circular platinised titanium anode around its inner wall.
  • the baths were subjected to magnetic stirring. pH was measured using universal indicator paper.
  • the 30V-2A power packs were used and obtained from Thurlby.
  • An aqueous platinum plating bath was prepared from 125 ml of 20Q solution (20 g/l Pt metal), 175 ml of water and 2 g of boric acid. The bath was used to plate a shaped part using the plating conditions of 2.10v, 066ma, 90°C, pH 8, to give 0.1836 g of bright silvery platinum in 60 mins. Two further layers were successively plated on the same substrate. Plating was continued for the second layer using the same plating conditions for a further hour to give 0.1768 g of bright silvery platinum. After the third hour, 0.1471 g of bright silvery platinum plated.
  • the bath was aged for 3 days at room temperature whereupon concentrated ammonia solution (0.3 ml) was added to the bath to restore the pH to 8.
  • a shaped part was plated using plating conditions of 1.61 v, 063ma, 90°C, pH8 to give 0.1460g of bright silvery platinum in 60 mins. Plating was continued using the same plating conditions for a second hour to give 0.2619 g of bright silvery platinum.
  • An aqueous platinum plating bath was prepared from 5g platinum tetraamine hydrogen carbonate, 8g boric acid and 300 ml water.
  • the bath was used to plate a shaped part using plating conditions of 1.6v, 075ma, 90°C, pH 8, to give 0.21 13 g of bright silvery platinum in 60 mins.
  • the bath was heat aged in an oven for 62 days at 90°C and was then used to plate a shaped part at 1.54V, 064ma, 90°C, pH 8, to give 0.1435g of bright platinum in 60 mins.
  • An aqueous platinum plating bath was prepared from 33g of platinum tetraamine hydroxide solution (9.4% Pt w/w), 300ml water and 9g boric acid.
  • An aqueous platinum plating bath was prepared from 125 ml 20Q solution (20g/l Pt), 175ml water and 4.95g boric acid. Using plating conditions of 1.7v, 063 ma, pH 7.5-8, 90°C for 30 mins then 1.89v, 080ma, 90°C, for 60 mins, gave 0.2838g of bright silvery platinum on a shaped part.
  • An aqueous platinum plating bath was prepared from 120ml 20Q solution (20g/l Pt as metal), 180ml water, 2g of boric acid (to neutralise the solution to pH 8), 5.7g sodium tetraborate decahydrate (pH now 10 at room temperature), followed by a further 1.5g boric acid to take the pH down to 8.5.
  • An aqueous platinum plating bath was prepared from 125 ml 20Q solution (20g/l Pt), 175ml water, 2g boric acid and 1g of sodium tetraborate decahydrate.
  • the boric acid content was increased to 5g.
  • An aqueous platinum plating bath was prepared from 120 ml P-salt solution (25g/l Pt), 180ml water, 2.5g boric acid and 1.5g of sodium tetraborate decahydrate.
  • An aqueous platinum plating bath was prepared from 125ml 20Q solution (20g/l Pt as metal), 175ml water, 4g of boric acid and 2g ammonium biborate tetrahydrate [(NhU ⁇ E ⁇ O / ⁇ h ⁇ O].
  • An aqueous platinum plating bath was prepared from 120ml P-salt solution (25g/l Pt as metal), 180ml water, 8g of boric acid and 1g lithium metaborate.
  • An aqueous platinum plating bath was prepared from 125ml 20Q solution (20g/l Pt as metal), 175ml water, 2.5g of boric acid, 1.5g lithium metaborate and 0.042g nicotinic acid.
  • An aqueous platinum plating bath was prepared from 120ml P-salt solution (25g/l Pt as metal), 180ml water, 8g of boric acid, 1g lithium metaborate and 0.042g nicotinic acid.
  • An aqueous platinum plating bath was prepared from 120ml 20Q solution (20g/l Pt metal), 180ml of water, 1 ml of 40% phosphoric acid and 1g of sodium metaborate hydrate.
  • a shaped part (see Figure 1 ) was plating using the conditions of 1.97V, 071 ma, 90°C, pH 8 to give 0.24288g of bright white silvery platinum in 90 mins.
  • a further 0.5g of sodium metaborate hydrate was added to the bath, along with 1.5ml of cone, ammonia.
  • a shaped part was plated using the conditions of 2.02v, 070ma, 90°C, pH 9 to give 0.1535g of bright white silvery platinum in 90 mins.

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Abstract

La présente invention porte sur un bain aqueux d'électroplacage de platine comprenant : a) une source d'ions platine ; et b) une source d'ions borate. Le bain aqueux d'électroplacage de platine peut éventuellement comprendre un ou plusieurs agents d'égalisation. L'invention porte également sur l'utilisation du bain d'électroplacage de platine.
PCT/GB2012/051599 2012-01-12 2012-07-06 Améliorations apportées à une technologie d'application de revêtement WO2013104877A1 (fr)

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CN201280066761.6A CN104040032B (zh) 2012-01-12 2012-07-06 涂覆技术改进
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WO2022129916A1 (fr) 2020-12-18 2022-06-23 Johnson Matthey Public Limited Company Solutions de dépôt électrolytique
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Publication number Priority date Publication date Assignee Title
WO2022129461A1 (fr) 2020-12-18 2022-06-23 Umicore Galvanotechnik Gmbh Stabilisation du taux de dépôt d'électrolytes de platine
DE102020007789A1 (de) 2020-12-18 2022-06-23 Umicore Galvanotechnik Gmbh Stabilisierung der Abscheiderate von Platinelektrolyten
WO2022129916A1 (fr) 2020-12-18 2022-06-23 Johnson Matthey Public Limited Company Solutions de dépôt électrolytique
DE102021107826A1 (de) 2021-03-29 2022-09-29 Umicore Galvanotechnik Gmbh Platinelektrolyt
WO2022207539A1 (fr) 2021-03-29 2022-10-06 Umicore Galvanotechnik Gmbh Électrolyte en platine
WO2024105359A1 (fr) * 2022-11-18 2024-05-23 Johnson Matthey Public Limited Company Solutions d'électrodéposition de platine à haut rendement

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CN104040032B (zh) 2017-12-22
CN104040032A (zh) 2014-09-10

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