US2030229A - Process of making compound structural material and shaped articles thereof - Google Patents

Description

[ pa ted 1 1, 1936 el borate.

"name a N6 Drawing;

L sci-a m. 9. 1

r 1 iiientiteteme tbshew process anamuiacturingastructural mateiial adapted-morepar ticularlyfor electrical purposes,;.withoutghowever,-.

being limited to this use.v

I softer metals, such as,.copper,- silveriandlso forth;

r I A; cohesive sponge-like qbody :was madeifi'om the a hard metalsran'd thegfluid soit metalswereallowed to be absorbed.thereinby inflltration. 1- V,

making composite structural material, and shaped articles thereof, *which consists principally of the following substances also may be present: titanium, vanadium, zirconium, tantalum, silver, gold, aluminium, cobaltgchromium, copper, nickel, platinum, tin, zinc ,or iron,.which arechosenso thatgatleast two of them rormatthe most only] 1 a superficial, alloy or solid-solution orpenetraa 1 tion while heatedwithor without pressure during a the compounding. ,-.More particularly the inven tion consists in a compositestructural material the v,lfollowing harder substances: 1 molybdenum, f titanium; vanadium; tungsten, tantalum, *zira conium and at least one from i the group-f the;

1 35;: and at least onesofteror flow-melting substance ofthesecond-grouo; b According to the invention also l h are sochosen that at least one of them-maintains its state of aggregation durlnglthe compounding 4c in the hot state and/or underpressure,

of the 1 here enumerated, harder imetals are: coni 1. 4

powder posslble. The meltghowever, can also byhc-beggranulsted. The powder thus obtainedkris 1 must be ,made bearing; inymind the properties AL MATERIAL A sHAP-EnARTIoL p I T v mm fl 'w rzkopn mi h/Two, sit-fizz} b Appliciation February, 19; 1932, 594,154 In Germany November 28,

Attempts have already, been madeto unitelhardmetals, such as, tungsten, or molybdenum, with l 'j Thepresent invention: comprises aprocess for tungsten and molybdenum while two ormoreof which comprises at; least one from the group "of, 7

According to the; present invention, ithe. proce dure is advantageously suchythat one orseveral V solidated in a-suitable manner from; thevmetal powders joxides or other compounds by melting or highly sintering, if desired also thoroughly worked mechanically, byhamnieringand rolling,"

X and thenycomminuting, preferably to. the finest- A uniformly Iandflnelycrystalline and has then oneor more soft metals above mentioned poured" thereoveri either ;,singly or 1 in admixture. The? cholce oI -botht-the hard and f the soft metals fo'cm sa-ace (Cl..151, 1)fl ,1 "1 r it isfdgsiredtdfimphrt to the body obetained, i. e. whether its hardness or 'its softness and shaping capability is to preponderate, or whether value is laid on small density, great'conductivity .or great resistance tofattacl rf' by atmospheric influences; i r j V c I'hereis also the choice of the'quantltyof hard and soft metal Itmaybe sufllcient for the'soft metalto-compris'e only 3 to 6% of the total quanv tity' ofthe structural material. Consequently it will act only as a binding-agent, for which purpose regularquantlties of this order of magnitude however; the soft metal acts not only as a binding v agent, but represents the structural material in the main, which is improved in its surface quality of l hardness by the addition of the hard metals; the quantity of soft metals can then be chosen equal to, or greater than, that ofthe'hard metals. The'amount of the 'lattermay thus be'limited to 10 and ev'enlowerpercentage. i The following examplesyof binarycomposite bodies corresponding to the invention may be ,lybdenum zinc'. '(2) Vzanadium-silve'r; vanadium-copper. I (3) Tungsten-silver; tungsten-chromium: tungsten' copperj tungsten-tin; t fifi n-zinc.

:The followi'rig 'examples of-ternary structural composite materials maybe givent- (4) Molybdenum silver-zirconium; "molybde- *num-vsilver-chromium; molybdenum-silver-titanium; molybdenum-chromium-titanium; molyb- '5 1' denum-chromium-copperf molybdenum -chromi f the substances:

um-tin; molybdenum-chromium-zinc; molybde i, num-coppertitanium; molybdenum-nickel-cop-f (5) Vanadium-silver-zirconium; 'vanadium sil' 40 var-chromium; "vanadium-copper-titaniurn; va nadium-copperchromium; vanadium'copper-i zirconium; vanadium-silver-copp'enl (6) Tungsten-silver alrconium;tungsten chroa miuni-zir'conium, tungstencopper zirconium: tungsten sllverititanium; tungstenchromium titanium; i tungsten-coppentitanlum; tungsten:

tintitaniunip'tungsten ainc-titanium; tungstensilver-chromium; "tungsten cjopper 7 chromium;,

tungsten-tin chrohiium; tungsten-,zlnc-chiomie um; tungsten -silver-vanadium;' tungsten copper vanadium;tungstenichromlum=vanadiumi tungsten vanadium -tltanium; tungsten-'nickel cop per. H V, "For making theistructural material the'procedure may be to pour the liquid soft metal over the compact hard metal powder. However, parts of the soft metal in solid form, more particularly in the form of powder, may be added to and intimately admixed with the powdered hard metal, and the whole may then be cast over with the remainder of the soft metal, which, however, is fused. In this case the wholeis preferably maintained at a temperature suchthatthe admixed soft metal powder melts as well and becomes incorporated with the soft metal which is cast on.

Finally, the procedure may also be such that both the hard and soft metals. are commlnuted, mixed and the whole thereupon heated to such an extent that at least the softmetal melts and incorporates the hard metal on cooling, which latter will become uniformly distributed in the cold soft metal. I

In these ways in the first place whole blocks or bars can be obtained of any shape or size, which are homogeneous throughout and from which the desired 'article can finally be made by heat treatment, e. g. recasting, or by mechanical working in the hot or cold, such as hammering, rolling, drawing, cutting.

It is also possible to obtain the desired article direct by inserting the metal powder mixture into a suitable mould and bringing at least the soft metal portion in it to fusion or softening it to such an extent that it takes up the hard metal part during cooling and imparts great homogeneity and uniform density to the bodybeing made.

Frequently, however, it is desired to make only certain parts of the body according to the invention, i. e. to make a composite body, such as, making a contact pin in which case only the outer contact surface is to be both hard and readily capable of being worked and resistant to oxidation, whilst the remaining part may not have the same resistance capability as the contact surface. In such a case the procedure is preferably such that, a mould open at the top is used, the lowest part of which is adapted to thecontact surface, on which the hard metal powder is applied in sufficient layers, after which the soft metal is poured or fused thereon, care naturally being taken that no air bubbles are entrained and consequently the casting is preferably carried out in a mould with discard head and in sucha-way that slow cooling which progresses from the bottom to the top is effected. A contact is then obtained which contains the hard metals at the contact surface and which possesses the desired general properties.

Similar results can also be attained by choosing the hard metals according to their density andtaking care that the metal bath in which the soft metals are fluid andthe hard metals are solid, remains in the hot liquid state for'a certain time, as a result of which the heavy hard metal powder can slowly move downwards and the bath is at least enriched in hard metals or metal powders in the lower part thereof,.whereupon the bath is allowed to set.

Thus one is in a position to make both shaped and unshaped bodies of the desired property which, on account of their suitablychosen hard metal content possess the desired strength and on account of their suitably chosen soft metal content, have good conductivity andmay be diflicultly oxidiz able and may be made with such prop erties far more economically and consequently more cheaply than this was hitherto possible with silver, gold-silver, platinum, and so forth, which metals, furthermore, are far too soft, are rapidly ficient conductivity, and which always shows the desired? mechanical, stability.

It is always, possible to add the hard metal not only in the form of ductile powder but also 'electrical and chemical in other form as short or, long wires which have been bundled or laid and which consequently have already been rendered compact and ductile during their preparation by hammering, drawing and so forth. These bodies can then be enclosed or melted round by the desired soft metals'as a result of which a composite body is attained from which the desired articles can be made. Thus it is possible to cast a soft metal (or metal mixture) cylindrically around such a cable'or the like. of tungsten or molybdenum wire. This can be more particularly carried out in a continuousprocess, such as in machines for pressing the soft-metal about the hard and then plates, or longer, somewhat cylindrical parts can be cut off from the cylindrical composite body which are used, as contact bodies. In these the wires of tungsten or molybdenum are then incorporated so that the electric current advantageously flows in the direction of the fibre of the wire.

When the composite body is made in the said manner in a machine for:pressing one metal around the other, the soft metal is united to the harder metal in the hot liquid state or at least in a plastic state produced by heating. Production is effected, therefore, both in the hot state and under raised pressure which can be increased in individual cases to betweeen 25 atm. and 50 atm. and even above.

The finely crystalline structure of the composite body sets in of itself, the harder metal obtained by melting or highly sintering either already possessing such structure or else acquiring it subsequently by mechanical working. If necessary, however, a particularly desired finely crystalline structure may be obtained by thermal treatments such as known per se in the metal working art, thus, for example, by rapid cooling or chilling of the composite body during the manufacture or by subsequent heating of the ready made article or body and subsequent rapid cooling thereof.

The material according to the-invention is not confined to any special purpose. Thus it can for instance be used as bearing, packing or stufilng box metal, particularly for steam turbines.

I claim:

1.-A. process for makingv an agglomerated structural material and shaped bodies thereof, containing at least one metal selected from a first group consisting of tungsten, molybdenum, and tantalum, and at least one metal selected from a second group, consisting of silver, nickel, cobalt, iron, said process consisting in first subjecting metal of the first group in the powdered form in which it is obtained from its compounds 01 ores, to a heat treatment at temperatures at least as high as sintering temperature, thereupon powdering the so compacted metal, thereupon mixing this powder with metal taken from the second group and consolidating this mixture by heat treatment at temperatures below the sintering temperature oiflthe metal of the first 2. In a processaccording to claiml, taking metal fromthefirst group amounting from about upto about 94% of the mixture,

,3. -A process of manufacturing an agglomer-; ated structural material and shaped bodies thereirom, containing at leastone metal selected from a group consisting of tungsten, molybdenum'and ,tantalumand at least one metal selected from a group consistingof silver, nickel, cobalt, iron,

copper saidprocess consisting in first heattreating granularinitial' metal taken from the; first groupin thepowdered form in which'it is ob,

:tained from its compoundsor ores attemperatures ,at'leastas high asisinteri'ng temperature,

thereupon powdering the so-compacted metal, then mechanically working the compacted metal, then powdering the so compacted metal and mixing it with metal taken from the second group,

thereupon heating/this mixture at a temperature atleast sufliciently high tomelt the metaltaken ,from'the second group but below a temperature at which the structure of (the metal of the first group is materially changed. a

4, A process of manufacturing anagglomerated structural material and shaped bodies therefrom containing at least one metal selected from a group consisting of tungsten and molybdenum, and aid-least one metal selected from a group consistingfofx, copper, silver, said process consisting in first heat treating granular initial metal taken. from the first group in the powaosoao M I 3 dered form in which it isobtainedfrom its co pounds or ores, said heat treatments to be effected at temperatures at "least as high as sinc tering temperature of theinetals taken, thereupon compacting the metal by allowing it to i cool down, then mechanically working the compacted metal, then powdering the so compacted metal and mixing it with metal taken fromthe secondxgroup, thereupon heating the mixture at a temperature at least sufliciently high to melt the metal taken from the second group, but at a lower temperature'than one at which the metal from the firetgroup is materially changed.

5. A process of manufacturingtan agglomerated structural material and shaped bodies therefrom containing at least onemetal selected from and at leastone metal selected from a group consisting of copper,-silver, nickel, said process consisting in first heat treatinggranular initial metal taken from the first group in the powdered form in which it is obtained fromits compounds or ores, said heat treatments to beeffected at temperatures at least as high as sintering temperature of the metals-taken, thereupon compacting the metal by allowing it to cool down,

then mechanically working the compacted metal, then powdering the so compacted metal and mixing it with metal taken from the second group,

-agroup consisting of tungsten and molybdenum,