Wear of Cobalt and a Nickel Alloy

The wear characteristics of a nickel-base alloj has hem cOmpare with a cobalt-base alloy. Both have hem investigated under abrasive and also adhesive wear conditiofU. Under abrasive conditions, the cobalt alloy wears at about half the rate of the nickel ailqy rom though they are approximately the same hardness. Under adhesive conditions, sliding against a hardened steel ring, wear of the nickel alloy is vastly superior to the cobalt alloy. The metallography of wear and the characteristics of the worn surfaces and wear debris COTTelate very well. Under abrasive conditions, wear occurs by de- lamination to produce platelike metallic debris. Under adhesive conditimu, the nickel alloy produces a protective oxide film with no evidence of adhesion. The cobalt alloy adheres to the steel disk with transfer from one surface to the other and with the production of lumps of metallic debris.