US2474039A - Method of forming composite metal having a nickel-plated beryllium-copper base and gold or silver bonded thereto by a copper-plated iron sheet - Google Patents

Description

jme' ma 3949 E. HDAWGNGM 2,47439 METHOD OF FORMING COMPOSITE METAL HAVING NICKEL PLATED BERYLLIUM-COPPER BASE AND GOLD OR SILVER BONDED THERETO BY A COPPER PLATED IRON SHEET Orgixml Filed Harsh 3 1945 2 Sheets-Sheet l 4r/NICKEL BERYLUUM coppa@ /COPPER RON x.

LAM P BLACK COPPER N ECME. BERYLLIUM COPPER LAMP BLACK 31m@ 2l, l949 E. H. DAVIGNON 2,474,039

METHOD OF FRMING COMPOSITE METAL HAVING' A NICKEL l .PLTED BERYLLIUM-COPPER BASE ND GOLD OR SILVER BONDED THERETO BY COPPER PLATED IRON SHEET Original Filed Harsh 3s 1945 i 2 Shasta-Sheet 2 mmmmm NICKEL soLDER\\" BERYLLIUM COPPER BERYLLIUM COPPER BERYLLIUM COPPER Patented June 21, 1949 METHOD OF FORMING COMPOSITE METAL HAVING A NICKEL-PLATED BERYLLIUM- COPPER BASE AND GOLD OR SILVER BONDED THERETO BY A COPPER-PLATED IRON SHEET Ermand H. Davignon, Attleboro, Mass., assignor to Metals & Controls Corporation, Attleboro, Mass., a corporation of Massachusetts Original application March 3, 1945, Serial No.

1946, Serial No. 666,442

3 Claims. (Cl. 29-189) This invention relates to composite metals and more particularly to composite metals having a lprecious metal surface and a beryllium-copper ase.

This application is a division of my copending application Serial No. 580,901, led March 3, 1945.

Among the objects of this invention are the provision of a composite metal having a precious metal surface and a beryllium-copper base; the provision of a composite metal of the class indicated which may be solution annealed Without blistering so that the composite metal may be easily formed, and yet may be subsequently treated to spring temper it; and, the provision of methods for forming such composite metals. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the steps and sequence of steps, and features of manipulation, which will be exemplied in the methods hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is fragmentary section through an intermediate for the production of the composite metal of the present invention;

Fig. 2 is a fragmentary section through another intermediate;

Fig. 3 is a fragmentary section through the finished composite metal prior to bonding;

Fig. 4 is a fragmentary section showing the composite metal ready for bonding;

Fig. 5 is a fragmentary section through an alternative embodiment of the finished composite metal prior to bonding; and,

Fig. 6 is a fragmentary section through still another embodiment.

Similar reference characters indicate correspending parts throughout the several views of the drawings.

Beryllium-copper alloy has been used as a base for a plate of sliver, gold or other precious metals. However, such composite metals could not be solution annealed because when such a treatment was attempted the composite metal blistered and the precious metal layer peeled.

Precious metal plates on a beryllium-copper base have been utilized in the past but these have been in the cold-roll-hardened state. A cold rolled beryllium-copper is not as hard or springy asfone which is ilrst solution annealed and then tempered. Such cold rolled plated beryllium- Divided and this application May 1,

copper composite metal was accepted heretofore since it was the only alternative available to a blistering and peelingcomposite metal.

According to the present invention a berylliumcopper alloy base metal and a precious metal surface layer are combined to form a composite metal which may be solution annealed, and which therefore may be tempered to a desired hardness and springiness. In the composite metal of the present invention the berylliumcopper -alloy base and the precious'metal surface layer are bonded together through a separating layer of a relatively infusible metal such as iron. By relatively infusible is meant a metal which will fuse with, or bond to, the adjacent metals only on a skin layer, so that the sliver is separated from the beryllium-copper with a iinite unalloyed layer of this blocking or separating metal, and further characterized by having a melting point several hundred degrees higher than the solution-quench temperature. An iron intermediate layer is .the preferred type. It is first coated with a layer of what may be termed an anti-oxidant metal, that is, one which protects the separating metal from oxidation. Suitable anti-oxidant metals are copper and nickel. The surface of the beryllium-copper base is likewise protected by such an anti-oxidant metal.

Referring now to the drawings,

Fig. 1 illustrates a beryllium-copper base which has been coated with a protecting layer of nickel. This coating may be applied in any desired manner, as by dipping, electroplating, spraying, etc. The nickel coating protects the beryllium-copper surface from oxidation.

Fig. 2 illustrates an intermediate layer of iron which is coated on both vsides by a protecting layer of copper. This copper layer may be applied in any desired fashion, as by dipping, electroplating, spraying or the like. layer not only protects the surface of the iron from oxidation, but aids in bonding together the beryllium-copper base and the precious metal surface layer.

Fig, 3 illustrates, with the layers in their relative positions, the composite metal ready for bonding. It will be noted that a surface layer of silver and a beryllium-copper base are joined together through a layer of copper, a layer of iron, a second layer of copper, a layer of vsolder and a layer of nickel.

Fig. 4 illustrates a means for bonding the layers-` together. The entire assembly is sandwiched 'between two sheets of iron which have beenfcated on the contacting sides with layers of lamp black.`v`

The copper l The two sheet iron Alayers are held imposition '--by clamps (not shown) which also serve to reface layer. It may be solution annealed without danger of the layers separating or blistering, and may be formed as desired by rolling operations, etc. 'For example, it may be rolled to a desired nal thickness with as many anneals in between rolling operations as are necessary, and after a nal solution anneal may be sold either in the soft form or heat treated to a spring temper as preferred. 1

Fig. 5 illustrates an alternative embodiment of the composite metal in which a beryllium-copper base is plated on both sides with a precious metal. In this instance the beryllium-copper base is initially plated on both sides with a protecting layer of nickel, and two intermediate layers and two precious metal layers are utilized, one on each side of the beryllium-copper base.

Fig. 6 illustrates a still further embodiment in which two beryllium-copper base layers form the outer surfaces of the composite metal while a silver layer forms the central layer. This embodiment is formed in the same way as the Fig. 5 embodiment, that is, a sandwich is formed utilizing two intermediate layers, only in this instance the order of the components is reversed from that of the Fig. 5 embodiment. The Fig. 6 embodiment is of value for purposes such as Where increased conductivity of the mass is desired and yet it is desired to retain the hardening quality of the whole mass.

The solder layer is of the customary type for the purpose and, if desired, a ux may be also used. The coating layers of anti-oxidant metal need only be of suiiicient thickness to prevent the formation of oxides on the beryllium-copper where it is to be bonded, and to prevent the formation of oxides on the separating metal layer. 'I'he coating may be put onelectrolytically to a desired thickness or may be put on by lamination, by dipping, etc., and then rolled down to the requisite thickness of a few ten-thousandths of an inch.

As specific examples of the formation of the composite metal of the present invention, the following are given:

Example 1 A sheet of pure silver, at least .010" thick, is used as the precious metal layer. It may be thicker if preferred and may be as thick as the beryllium-copper on which it is to be plated. In the present example the pure silver is .035" thick. A beryllium-copper layer .750" thick and consisting of an alloy containing 2.25% beryllium by weight and the remainder copper, is electroplated with pure nickel to a thickness of approximately .00025". A sheet of iron .010" thick and consisting of low. carbon iron is electroplatedA with pure copper to a thickness of approximately 00025". The elements are now assembled with the silver on top, next the plated iron, next a layer of solder and then the final layer of the plated berylliumcopper. A' ux need lnot be used. On top of the silver is placed a sheet of 1,4," iron covered with lamp black. A similar sheet is placed outside the beryllium-copper. The lamp black provides a reducing atmosphere and also prevents the silver and the beryllium-copper from sticking to the iron. The assembly is then clamped to hold the whole pack together and heated at 1580 F.

for a predetermined time depending upon its volume, e. g. a 3" wide by 14 long ingot would take about 35 minutes. The assembly is then taken out of the oven, the clamps tightened before cooling, and the whole then permitted to cool.

The resulting ingot of aY silver plated berylliumcopper base is then ready for desired forming operations, which may include solution annealing.

Example 2 An ingot is formed as described in Example 1 except that the beryllium-copper base is plated on both sides with nickel, and two sheets of copper plated iron and two sheets of silver are utilized. The elements are assembled with a layer of silver on top, next a layer of the plated iron, next a layer of solder, next the plated beryllium-copper, next a layer of solder, next the other layer of the plated iron and then the other layer of silver. 'Ihe assembly is then bonded as described in Example 1. i

The resulting ingot of beryllium-copper plated on both sides with silver is then ready for desired forming operation which may include solution annealing.

Example 3 A ,composite metal having a central layer of silver and a beryllium-copper layer on each side is formed as follows:

Two beryllium-copper layers .120" thick and consisting of an alloy containing 2.25% beryllium by weight and the remainder copper are electroplated with pure nickel to a thickness of approximately .0002552 The elements are now assembled With a silver layer .140 thick in the center, next the plated iron on each side of the silver layer, next a layer of solder approximately .003" thick outside each of the plated iron layers and then outside of eachsolder layer the final layer of the plated beryllium-copper. The sandwich assembly is then bonded in the way described in Example 1.

The resulting ingot of a silver cored berylliumcopper is then ready for desired forming operations which may include solution annealing.

The solder used in the foregoing examples is of the usual type, as for example, a solder con- I sisting of approximately 30% silver and 70% copper.

In view of the above, it will hev seen that the several objects of the invention are achieved and other advantageous results attained.

. As many changes could be made in the above methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

l. The method of forming a composite metal having a surface of a metal selected from the group consisting of gold and silver, and a beryllium-copper base comprising coating at least one side of said base with nickel, coating a sheet of iron with a protecting layer of copper, and then bonding the precious metal layer to said iron sheet and bonding said iron sheet to said base layer.

2. The method of` forming a composite metal having a precious metal surface of gold and a acuoso 5 beryliimn-copper base complaint coating at least one side of said base with nickel, coating a sheet of iron with copper, and then bonding the precious metal layer to said iron sheet and bonding said iron sheet to said base layer.

3. The method of forming a composite metal having a precious metal surface of silver and a. beryllium-copper base comprising coating at least one side of said base with nickel, coating a sheet of iron with copper, and then bonding the precious metal layer to said iron sheet and bonding said iron sheet to said base layer,

H. DAVIGNON.

REFERENCES CITED The following references are of record in the tile of this patent:

Number UNITED STATES PATENTS Name Date Martin May 16, 1899 Davignon May 16, 1926 Steenstrup May 5, 1931 Maskrey Feb. 7, 1933 Kammerer Apr. 18, 1933 Moore Oct. 24, 1933 Armstrong Apr. 9, 1935 Davignon Dec. 17, 1935 Hodson Jan. 16, 1940 Huston et al Dec. 24, 1940 Deutsch Jan. 13, 1942

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