US2074474A - Tungsten base alloy for points of gold nibs - Google Patents

Description

Patented Ma.- 23, 1937- PATENT oFFncr.

TUNGSTEN 'BASGI? ALLOY FOR POINTS or OLD NIBS Alfred Jedele, Hanau-on-thc-Main, Germany, as-

signor to W. C. 'Heraeus Gesellschaft mit bcschrankter Haftung, Hanau-on-the-Main, Germany, a German company 7 .No Drawing. Original application January 2,

1935, Serial No. 105. Divided and this application September 26, 1936, Serial No. 102,817

1 5 Claims. (01. 75-176) This application is divided out from my copending application Serial No. v 105 filed January 2, 1935, and relates to alloys for the points of gold nibs.

Many alloys for thepurpose specified have atread'y become known. There are tungsten-base alloys whose balance-is made up by metals of the platinum group. There areother alloys with a base of'platinum-group metals, and up to 10% 1 tungsten, with a small percentage of nickel or the 7 like. Lastly, there are alloys with iron, copper, or nickel as the base, with a small percentage of two metals of the platinum group, and of tungsten. I

The many alloys of these types which-have become known, are hard and sufliciently acid-proof, so that they do not wear rapidly, and are not attacked by ink. Howevr', they are so brittle that it is difficult to split the nibs, and this operation must be performed by means of a very thin and rapidly rotating disc of copper moistened with-a paste of emery. This is obviously an undesired complication which ought to be eliminated.

It is an object of my invention to provide an alloy for the points of gold nibs which is as hard and acid-proof as the aforesaid known alloys, but at the same time possesses a, high degree of tenacity so that nibs having points of my novel alloy, can be split simply, by means of a blade or shearing device;

To this end, I compound 'my novel alloy of tungsten as the base to which are added a metal of the iron group, i. e., iron, nickel, or cobalt, palladium, and a hard metal of the same group, i. e.,-osmium, ruthenium, rhodium, or iridium. The percentage of palladium should be higher than that .of the hard metal.

I have found that the cgmposition of an alloy which can be cut by the aforesaid cutting or shear- 'ing means, must fulfill certain conditions. The base of'the alloy is tungsten at the rate of 65 to 80% of the alloy. However; up to 20% of the tungsten may be'replaced by molybdenum, or tantalum, or bycarbidesof these metals. To this base I add metals of the iron group, i. e., iron, nickel, or cobalt, at the ratelof to 20%. Iron and nickel are less eflicient than cobalt, so that cobalt is normally preferred:

Thenovel feature of my alloys is that their content of precious metals consists for the major part; preferably at the rate of 8 to 20%, of pal-,

' ladium, and for the minorpart, preferably at the rate 'of 2 to 10%, of hard. metals of'the platinumgroup, i. -e., osmium, or other hard metals.

55 Ruthenium is particularly suitable as a constitucut of my alloys, but rhodium and iridium may also'be used. i

My alloys may be prepared uniformly in any suitable manner, for instance, in electric are or highfrequency-induction furnaces, preferably with inserted crucibles. I 1

Heretofore, the soft metals of the platinum group, i. e., platinum and palladium, were not added at comparatively high percentages, as the alloys for the points of nibs became too soft. However, I- have established thesurprising fact that by adding palladium and a small percentage of osmium to abase of tungsten-with iron, nickel, or cobalt, alloys are obtained. whose hardness is equal to that of alloys consisting principally of the said hard metals but whose tenacity ,is very much superior to that of the aforesaid alloys, and my novel alloys can therefore be out. The tenacity of alloys is ascertained by placing a particle of the alloy whose diameter may be 1.3 millimeters, between a pair of jaws, and compressing it until-it is crushed. The crushing strength is determined by the tenacity; and not by the hardness, of the alloy under test. It amounts to only afew kilograms in brittle alloys, but may be 50 kilograms, and more, for tenacious alloys.

Asprefered examples of my preferred alloy,

2 I give the following:

Example I Per cent Tungsten Cobalt l0 Palladium 20 Osmium 5 Example II Per cent Tungsten Cobalt 10 Palladiumi n'nn 8 Iridium 2,

' Example III Per cent Tungsten 65 Cobalt 10 Palladium 15 Ruthenium 10 My improved alloys have crushing strengths between around 50 and 10 kilograms. whereas the crushing strengths of several known commercial alloys varies between 6 and 30 kilograms.

To obtain my high tenacity the percentage of tungsten must be high. The percentage of precious metals may exceed 25 and should comprise more soft than hard metal, The percentage of ignoble metals should not exceed 20. Asthe metal of the iron group! I prefer -to employ cobalt and as the hard metal of the platinum 'group, osmium is preferred. Ifruthenium or rhodium is employed instead of'osmium, the alloys become less tenacious and softer, but still are superior to known commercialalloys .with respect to their crushing strength.

My novel alloys have the good property that they can be welded to gold nibs 'on account of their content of cobalt while, as known pure tungsten and manyalloys 3 mm, and metals of the platinum be welded directly to goldnibs.

I claim: g 1. An alloy for points of gold nibs consisting of 65% of tungsten, 10% of cobalt, of palladium, and 5% of osmium. 20 2. An alloy for points of gold nlbs con'slstsing of group. cannot of tlmgsten, m'olybdetheamount of palladium amount of osmium.

- rhodium and iridium, the

80% of tungsten, 10% -of cobalt, 8% of palladium, and 2%.ofiridium. 1

3, An alloy for points of goldnibs co of from to tungsten, from 5% to 20% of a metal of the iron'group, from 2% to 10% of osmium, and from 8% to 20% of palladium,

4. An alloy-for points of gold nibs of from 65% to 80% of tungsten, from5% fo20% from 8% to 20% of.

of a metal of the iron group,

palladium and from 2% to 10%ofa hard metal of the class composedof osmium, ruthenium,

amount of palladium being greater than the amount of the metal of the class of hard metals. g

5. An alloy for points of gold nlbs 'of'65% of tungstenf10% of cobalt, 15% of palla dlum, and 10%, of ruthenium.

being greater thanthe m JEDELE; 20