US2031113A - Alloys - Google Patents

Description

Patented Feb. 18, 1936 2,031,113 v ALLOYS Robert H. Leach, Fairfleld, Conn, assignor to Handy & Harman, New York, N. Y., a corporation of New York No Drawing.

Application April 17, 1934, Serial No. 720,949. Renewed July 9, 1935 5 Claims. .(Cl. -1)

This invention relates to silver alloys and is concerned more particularly with a novel silver alloy, which may be given suitable physical characteristics selected in accordance with the purposes for which the alloy is to be used, and which has substantial resistance to the action of various corrosive and tarnishing agents.

The new alloy contains a relatively large amount of silver, ranging from about to about 99.5%, a small amount of beryllium ranging from about 0.10% to about 1.75%, and a quantity of base metals, such as copper, tin, zinc, and cadmium, used alone or in combination, and constituting the remainder.

The addition of the beryllium within the range of amounts specified gives improved physical properties to alloys of silver and the base metals mentioned, and these properties can be varied considerably. For ordinary purposes, the amount of beryllium willnot exceed about 1.75% and will preferably be much less than that and approximating 0.5%.

' The use of beryllium affords a further advantage in that it increases the resistance to the action of certain tarnishing agents. Silver alloys exposed to the atmosphere are attacked by tarnishing agents in the course of time and standard silver-copper alloys when so exposed take on a tarnish which varies from light yellow through different shades of brown to black and purple, depending upon the length of the exposure, the concentration and character of the tarnishing agent and possibly other factors. When a silver alloy containing beryllium in the amounts above specified and standard silver-copper alloys are exposed for the same length of time to an atmosphere containing certain types of tarnishing agents, it is found that while the standard alloys take on a tarnish of the characteristic colors above mentioned, the new alloy acquires a film which is light gray and thus less conspicuous and noticeable on the light colored metal than the films which appear on the standard alloys.

In making up alloys in accordance with the principles of the invention, different base metals, alone or in combination, and different combinations of those metals are employed according to the purposes for which the product is to be used. The effects of employing the difiere'nt base metals mentioned in silver alloys are all well known to metallurgists and by using its base metals or combinations thereof with varying amounts of beryllium, it is possible to produce alloys which are sufllciently malleable and ductile to be rolled into sheets or drawn into wire and to produce finished sheets which are smooth and capable of taking a high polish. Ordinarily, it may be said that increasing the beryllium content in the alloy increases the tendency to brittleness and the surface of the rolled sheet may be rough and diflicult 5 to polish. Probably in the majority of cases, 0.5%

or less of beryllium will be the most desirable amount to use since when present in that proportion, beryllium ofiers its characteristic advantages and does not result in physical properties of 10 an unsatisfactory character.

Examples of the new alloy are as follows:

Example No. 1

In producing the new alloy, the beryllium is preferably employed in the form of a master alloy containing silver or copper and about 10% to 12% or 13% of beryllium, and such a master 45 alloy is used because beryllium is readily oxidized and is, at the present time, expensive. Unless a master alloy is used, there may be losses of the beryllium by reason of oxidation which would add considerably to the cost of the product and 50 also difficulties are likely to be encountered in obtaining the desired fusion.

Although I refer to copper as the base metal used in the new alloy, it is to be understood that, for the purposes for which these alloys are used, 65

ranging from about 90% to about 99.5%, beryllium ranging from about 0.1% to about 0.5%, and the remainder copper.

3. An alloy which consists of about 92.5% of silver, beryllium ranging from 0.1% to about 5 1.75%, and the remainder copper.

4. An alloy which consists of about 92.5% of silver, beryllium ranging from 0.1% to about 0.5%, and the remainder copper.

5. An alloy which consists of about 92.5% of 10 silver, about 7% of copper, and about 0.5% beryllium.

ROBERT H. LEACH.