White-colored copper alloy with reduced nickel content

Abstract

Disclosed is a white-colored copper alloy comprising by weight up to 30% zinc, up to 20% manganese, up to 5% nickel with the balance copper. This alloy may have from 6% to 25% zinc, from 4% to 17% manganese, from 0.1% to 3.5% nickel and the balance copper. The balance copper in the alloy may further contain at least one of: up to 0.5% of at least one of the group which consists of Sn, Si, Co, Ti, Cr, Fe, Mg, Zr, and Ag; and up to 0.1% of at least one of the group which consists of P, B, Ca, Ge, Se, Te. It may also contain up to 0.3% Zr by weight. The alloy may have an electrical conductivity greater than 2.5% IACS at eddy current gauge exciting frequencies between 60 kHz and 480 kHz.

Description

[0001]The invention claims the benefit of priority of U.S. Provisional Patent Application No. 61 / 095,719, “WHITE-COLORED COPPER ALLOY WITH REDUCED NICKEL CONTENT”, filed on Sep. 10, 2008 and U.S. Provisional Patent No. 61 / 095,733 “IMPROVED WHITE-COLORED COPPER ALLOY WITH REDUCED NICKEL CONTENT” filed on Sep. 10, 2008.FIELD OF THE INVENTION[0002]This invention relates to white- or silver-colored copper-based alloys with reduced nickel content compared to standard alloys of similar color.BACKGROUND OF THE INVENTION[0003]Copper base alloys are widely used for their combination of ease of fabrication, corrosion resistance, electrical and thermal conductivity, and availability in a wide range of attractive colors. They are the preferred material worldwide for circulating coinage, in many cases as part of multi-layer composite systems. In addition, recent research has shown copper and copper alloy surfaces can be manufactured to be antimicrobial, inactivating a variety of microorganisms i...

AI Technical Summary

Benefits of technology

[0017](3) It is another feature of at least one embodiment of the present invention that iron may be used in place of or in addition to the nickel for improved color and

[0022]Among the advantages of at least one embodiment of the present invention is that the white-colored copper-base alloy of the invention has antimicrobial properties. The inactivation rate of bacteria placed on a surface composed of the alloy of at least one embodiment of the present invention is superior to that of other copper-based alloys of similar color, and is also superior to what would be expected from the rates found with commercial binary alloys of copper with components of the proposed alloy.

Problems solved by technology

Alloys with a whiter color (reflecting all light wavelengths more uniformly) are also available, although it is generally difficult to achieve good white colors without strong reddish or yellowish overtones, particularly after the material has tarnished or partially oxidized.

Unfortunately, nickel is more expensive than most other alloying elements, and has been implicated as a major contributor to increased cases of allergic contact dermatitis when used in contact with human skin and other tissue.

While attractive and durable, the alloy is expensive due to the high Ni content, since Ni is typically over twice the price of copper.

Bronwite is very white, very fluid and has a relatively low melting temperature which makes it excellent for small, thin and delicate castings such as costume jewelry, but it contains enough Pb to cause problems with current Restrictions on Hazardous Substances (RoHS) and Consumer Product Safety regulations.

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