Nickel Silvers

Overview

Nickel silvers are alloys that contain copper, nickel, and zinc. They are also called nickel brasses, the silver refers to their attractive silver luster. The nickel silvers have moderately high strength and good corrosion resistance. The cast nickel silvers are copper, tin, lead, zinc, nickel alloys. They too are named for their silvery luster. They have low to moderate strength and good aqueous corrosion resistance. They are used in the food and beverage handling equipment, decorative hardware, electroplated table ware, optical and photographic equipment and musical instruments. The copper silvers are designated as UNS C73500 through C79800, the cast alloys are UNS C97300 to C97800.

The microstructures of the nickel silvers are predominantly single phase solid solution alloys. The wrought nickel silvers contain between 7 and 20% nickel, and 14 and 46% zinc. The structure of the higher zinc alloys is a two phase structure, similar to that of the high zinc brasses. The nickel is soluble in copper, so it remains in solid solution with the copper. Zinc has limited solubility in copper. Alloys with more than approximately 32% zinc consist of alpha and beta phases. These alloys solidify over a wide range of temperatures, the resulting cast microstructure contains cored dendrites, or dendrites with a composition gradient across the thickness. The composition of the material in between the dendrite arms is rich in zinc and nickel. The wrought structures of the alloys with less than 32% zinc are single phase equiaxed, twinned grains of alpha copper. The two phase alloys contain a mix of alpha and beta grains.

NOTE: The file size of the Larger and Largest View of the Micrographs are substantially larger than the thumbnail shown. The Larger View images range in size from 11K to 120K depending on the image. The Largest View images range in size from 125K to almost 500K.