US1668642A - Manufacture of alloys - Google Patents

Description

May 8, 928. 1,668,642

w. M. GROSVENOR ET A1..

MANUFACTURE oF ALLoYs" Filed Feb. 5. 3.92.5

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INVENTORS ATTQRNEYS Patented May 8, 1928.

UNITED STATES PATENT OFFICE.r

WILLIAM I. GROSVEN'OB AND VICTOR P. GEBSHON, 0F NEW YORK, N.

'Y,; SAD) GERSHON ASSIGNOR-TO SAID GROSVENOR.

IANUFACTURE F ALLOYS.

Application led. February 3, 1925. Serial No. 6539.

Our invention relates to improvements in the manufacture of alloys and more particularly to base alloys adapted for the manufacture of white gold and method of making white gold therewith. As is known in the art, white gold is an alloy of gold, nickel and zinc, sometimes containing also one or more other metals such as copper or palladium. White gold was formerly made by melting for example parts gold and adding to the molten gold and melting therein 4 parts of' nickel and 1 part of zinc by -weight, the Wholebeing covered with a suitable flux. The main diiliculty with this method was that, in spite of the flux, more or less zinc is volatilized and lost so that the resulting alloy is variable and such variations, particularly in respect of the quantity of zinc, result in an inferior if not useless gold alloy, and only in the hands of skilled manufacturers of alloys is it possible to obtain commercial results, and even then such alloys often contain oxides produced vby the oxygen from the air of hydrogen compounds caused by the action of hydrogen from the moisture ofthe air, which render the alloy excessively brittle. Therefore, the process is not well adapted for the average jeweller to carry out. .Most jewellers, furthermore, prefer to make up their own gold, because the gold they require varies as to number of karats and by making up their own white gold from line gold and base metal they can get any karat gold they desire and do not have to carry in stock substantial quantities of made up gold of different karats involving relatively large carrying charges. To meet this demand of the jewellers attempts have been made to supply the jewellers with base metals or alloys which the jewellers might readilyF alloy with fine gold in any desired proportion. The desideratum has been a base alloy containing nickel and zinc in proportions to make white gold. In the lirst mentioned method of making white gold by adding the unalloyed nickel and zinc to the molten gold, it is known that the zinc should be about one fifth of the base metal, e. g. if nickel and zinc alone are used to form the base metal to be alloyed with the fine gold, 4 parts of nickel to 1 part by weight of zinc would be used, and if for example it were desired to produce an 18 karat white gold, 4 parts nickel and 1 part zinc and 15 parts of line gold would be used. A base alloy of about 80% nickel and 20% zinc suitable to be thus alloyed `with gold, has not, so far as we are produced. It is well known/that zinc boils and vaporizes at a temperature well below the melting point of nickel and if nickel be added to molten zinc it is found that only a relatively small percentage of the nickel will be taken up, while if zinc be added to molten nickel or the two heated together to a temperature sullicient to melt them, a large part of the zinc volatilizes making it impossible to obtain a resulting nickel-zinc alloy .of predetermined composition of anything like thek 80-20 proportion, which must be quite closely adhered to in so far as the proportion of zinc is concerned if a satisfactory white gold is to be obtained.

To obtain an alloy which jewellers might melt up with gold to make such white gold, it has been suggested that an alloy containing the zinc and about equal parts of copper and nickel be used. This base alloy contained over 40% copper. By using this copper it was found that over 15% of zinc and about 40% of nickel could be gotten in the resulting base alloy of nickel, copper and zinc. When, however, this base alloy was melted with fine gold to make 18 karat or other usual karat white gold, it was found that the resulting gold was tinged with yellow or red and oil' color and did not have that desirable whiteness substantially like that of platinum.

To avoid this and reduce the amount of -copper in the resulting gold it has been suggested that two metals be furnished the jewellers, one being merely nickel and the other an alloy of copper and zinc with or without a small amount of nickel and/or palladium. In this way the amount of copper introduced into vthe final gold has been reduced to about 10% 4of the base metal,

whereby the resulting goldis of much better color. This method has the disadvantage however, that two base metals must be carefully weighed out as well as the gold and a mistake in weighing out either of the two base metals is likely to result in a subst-antial change in the proportion of zinc in the resulting alloy which in turn will result in an inferior white gold if not a useless alloy. Likewise mistakes are frequently aware, been heretofore made by interchanging one base metal or alloy for another. Also there is danger of loss of zinc by volatilization. The method is therefore not only inconvenient but quite dificult of manipulation, uncertain in result, and a single base alloy suitable for melting with fine old in proportions to make 18 or other usua karat gold has been long sought.

To accomplish this result we have produced a new base metal comprising a substantially uniform and homogeneous alloy containing nickel and zinc, or a material containing nickel and zinc alloyed together, the zinc being about 20% of the alloy or material and the nickel about 80% (or if some other metal or metals are incorporated, the nickelbeing about 70% or over, the alloy or material having the characteristic that when melted and allo ed for example with 3 times its weight of ne gold, the resultant gold alloy not only exhibits a whiteness substantially like that of platinum but it also is capable of being cast and rolled for making jewelry. We have further' discovered that such a base alloy containing about 20% zinc can be produced by melting the zinc and nickel (with or without a small amount of other metal or metals) under pressure whereby the volatilization of the -zinc is prevented so that alloys of nickel and zinc and containing a substantially accurate predetermined percentage of zinc can be satisfactorily obtained.

For this purpose we prefer touse an apparatus like that shown in the accompanying drawings in which Fig. 1 is a vertical section of the apparatus. Fig. 2 is a horizontal section taken on the line 2-2 of Fig. 1, and

Fig. 3 is a vertical section of the lower part of the apparatus taken on the line 3--3 of Fig, 1.

hel apparatus shown comprises a cast iron dish-like container 4 provided with flanges 5 to which a cover member 6 may be tightly secured by bolts 7, the cover acting to seal the container air-tight. The container is lined with a thick layer 8 of heat insulating material ysuch as asbestos orisilocell. Fitting snugly within this heat insulating material is a trough or vessel 9 of carbor'undum, within which are located a plurality of dishes 10, 11 and 12, made of suitable refractory material, a layer of carbon resistor grains 13 extendin around the bottom, sides and ends of the dis es 10, 11 and 12 between them and the inside walls of carborundum vessel 9.

Screwed into the ends of the container 4 are cast iron pipes 14 and 15 provided on their outer ends with flanges 16 and 17 respectively. Carbon or graphite electrodes -18 and 19 extend through this pipe respectively and through the end walls of the vessel 9 into the carbon resistor grains 13 in order to make electrical connections therewith. The electrodes 18 and 19 are held messes .their outer endsfrom which lead flexible electrical conductor strips 22 to the heavy electrical conductors 23 and 24 respectively. The conductors 23 and 24are held in bakelite bushings 25 and 26 respectively secured into plates 30 and 3l, vwhich plates are secured to fianges 16 andi17 wherebythe bushings are secured with respect to and close the outer ends of the pi es 14 and 15 respectively. When in use t e dishes 10, 11 and 12 are preferably covered on top with a clay plate 27. The cover 6 has an' iron pipe 28 screwed into an opening therethrough'. The pipe 28 is flanged at its outer end and -to this iiange is secured an apertured disc 32. A bakelite bushing is screwed into the aperture of the disc 32 and through this bushing extend electrical connections to a thermocouple 33 for measuring the temperature'in one of the dishes. The cover 27 is suitably apertured to permit the insertion of thermocouples therethrough into the other respective dishes.

The apparatus described provides a suitable electric furnace within which the new alloy may be made. By applying a suitable potential to the electrodes 18 and 19, current will pass through the body of carbon resistor grains 13 causing the production of an intensive heat therein to heat the material placed within the dishes 10, 11 and 12. The cover 6 is provided with a pressure gage 34 for measuring the pressure within the furnace and also with a pipe connection 35 through which gas under pressure may be introduced into the furnace.

In operation we place the nickel' and zinc in the proper proportions and in the form of shot or line pieces, in the dishes 10, 11

`and l2, and cover the metals'with a suitable quantity to heat the metals in the vesselsy to alloying temperature. Or, instead of being evacuated, the air may be removed from the apparatus by displacement with nitrogen gas. Also the atmosphere should be preferably free of hydrogen which may be generated by the action of CO or C on the moisture in the air. When making an alloy of 20% zinc and 80% nickel it is ordinarily suilicient to maintain the pressure in the apparatus at from 10 to 15 atmospheres. However, other metals includi'n copper may be substituted rfor part vof t e nickel but for reasons above given, we prefer to keep the percentage of copper to about 10% or less and the percentage of nickel to about or over. The alloy has a melting point Well above the boiling point of zinc at atmospheric pressure, but by melting and alloying under pressure, any substantial amount of zinc is prevented from boiling oii or being lost to the alloy by volatilization. The properties of the alloy seem to be seriously affected by small amount of various impurities and by alloying in an atmosphere ofan inert gas such as nitrogen, the likelihood of such impurities .becoming incorporated in the base alloy as well as loss by oxidation of metal is materially reduced.

The resulting base alloy may be readily alloyed with 3 times its weight of ine gold to make 18 karat gold or any usual proportion and this is easily done by the various jewellers Vin a manner with which they are accustomed. vThe vresultant gold alloy not only exhibits a whiteness substantially like that of platinum but it is also capable of being readily cast and rolled for making many kinds of jewelry. It will be understood that any other suitable type of furnace may be used instead of that described.

While we have described our improvements in great detail and in connection with a preferred embodiment thereof, we do not desire to be limited to such details or embodiment since many changes and modifications may be made and the invention embodied in Widely dierent forms without departing from the spirit and scope of the improvements in their broader aspects. Hence we desire to cover all modifications and forms coming within the language or scope of any one or more of the appended claims. A

What we claim as new and desire to secure by Letters Patent is:

1. A substantially uniform and homogeneous alloy containing about 80% of nickel and about 20% of zinc, having a melting point above the boiling point of zinc and having the characteristic that when alloyed with 3 times its weight of tine gold the resultant gold alloy not only exhibits a whiteness substantially like that of platinum but it also is capable of being cast or rolled for making jewelry.

2. A substantially uniform and homogeneous alloy containing nickel and zinc, the zinc being about 20% of the alloy and the nickel about 70% or over, the alloy having a melting point above the boiling point of zinc, and having the characteristic that when alloyed with 3 times its weight ot' tine gold the resultant gold alloy not only exhibits a whiteness substantially like that of platinum but it also is capable of being cast or rolled for making jewelry.

3. A substantially uniform and homogeneous alloy containing nickel and zinc, the zinc being about 20% of thealloy and the nickel about 70% or more, and having the characteristic that it is capable ot being alloyed with 3 times its weight of line gold producing a resultant gold alloy which not only exhibits a whiteness substantially like that of platinum but which also is capable of being cast or rolled for jewelry.

4. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture of about 20% zinc and about 807;) nickel to alloying temperature in an inert atmosphere and under pressure suiiicient to prevent any substantial volatilization of the zinc.

5. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture containing zinc in the proportion ol about 20% and nickel in the proportion of about 7 0% or over, to alloying temperature and under pressure sufiicient to prevent any substantial volatilization of the zinc from the mass.

6. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture containing zinc in the proportion ot' about 20% and nickel in the proportion of about 70% or over, to alloying temperature in an inert atmosphere substantially free of hydrogen and oxygen and under sufficient pressure to prevent any substantial volatilization of the Zinc from the mass.

7. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture containing zinc in the proportion of about 20% and nickel in the proportion of about 70% or over, to alloying temperature in an atmosphere of nitrogen and under vsutlicient pressure to prevent any substantial volatilization of the zinc from the mass.

8. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture of about 20% zinc and about 80% nickel to alloying temperature and under pressure suicient to revent any substantial volatilization of tiie zinc.

9. The method of making a base alloy capable of being alloyed with gold to make white gold, which consists in heating a mixture containing zinc in the proportion of about 20% and nickel in the proportion ol about 70% or over, to alloying tempetrature and under pressure sufiicient to prevent any substantial volatilization of the zinc from the mass, and with a flux covering the upper surface of the batch.

10. A single substantially uniform and' of about four parts to one part respectively, having a complete melting point above the normal boiling point of the zinc therein and producing when alloyed with fine gold in proportions to make 18 karat gold a gold alloy exhibiting substantially the whiteness of platinum and adapted for casting or Jthe characteristic that when alloyed with rolling.

11. The method of making a base capable of being alloyed-With gold to make white gold which consists in heating a mixture consisting mainly of nickel and containing about 20% Zinc, to alloying temperature under pressure suicient .to prevent any substantial volatilization of the zinc.

12.'The method of making a base capable of bein alloyed with gold to make white gold Wi consisting mainly of nickel and containing` about 20% zinc, to alloying temperature in an atmosphere of nitrogen and under pressure suicient to prevent any substantial volatilization ofthe zinc.

13. An alloy material containing zinc and nickel alloyed together, the material containing about 20% zinc 'and about 70% or over of nickel and having the characteristic that when alloyed with 3 times its weight of line gold, the resultant gold alloyfnot only exhibits a whiteness substantially like that of platinum but it 'also is capable of being cast or rolled for jewelry.

14. An alloy material containing zinc and nickel alloyed together, the material containing about 70%. or over of nickel and having the characteristic that when alloyed with 3 times its Weight of fine gold, the resultant gold alloy will no t only exhibit a whiteness substantially like that of platich consists'in heating a mixture.

num but it also is capable of being cast or rolled for jewelry.

15. 'Ihe method of making white gold which consists in first making a base alloy material of zinc and nickel alloyed together, the material containing about 20% of zinc and about 70% or over of nickel and having 3 times itsweight of fine gold, the resultant gold alloy will not only exhibit a whiteness substantially like that of platinum but it also is capable of being cast or rolled for jewelry and then alloying this base alloy with gold in proportions to make white gold.

16. The method of making white gold which consists in first forming a base alloy material containing zinc and nickel alloyed together, the material containing about 70% or over of nickel and then alloying this base alloy material with gold to produce white gold.

17. The method of making white gold which consists in lirst forming` a base alloy material containing zinc and nickel alloyed together, the material containing about 70% oiwer of nickel and having the characteri'stic that when alloyed with 3 times its weight of fine goldthe resultant gold alloy not only exhibits a whiteness substantially like that of platinum but also is capable of being cast or rolled to make jewelry, and then alloying said base metal with gold in proportions to produce white gold.

In testimony whereof we have signed our names to this specification.

WILLIAM M. GROSVENOR. VICTOR P. GERSHON.

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