Walbar Inc.

Patrick R Lavery

Bernard R Rose

Coated nickel, cobalt or nickel-cobalt superalloy bodies having increased resistance to oxidation, corrosion and thermal fatigue at high temperature are produced by applying a thin layer of a platinum-group metal, siliciding and heating to an elevated temperature to diffuse and integrate the silicided platinum-group metal into the surface of the superalloy body. Then the superalloy body is exposed to a diffusion powder composition containing sources of aluminum or aluminum/chromium metals and heated in a hydrogen or inert gas atmosphere to an elevated temperature to codeposit and diffuse aluminum or aluminum and chromium into the silicided platinum-group metal-treated surface layer. Finally, the superalloy body is heated to its solvus temperature to form a ductile protective surface layer having an outer zone comprising a platinum-group metal aluminide, ductilized by the solutioning therein of beta chromium, and an inner stabilizing zone of silicided platinum group metal comprising from 3% to 20% by weight of silicon.

Platinum group silicide modified aluminide coated metal superalloy body

Process for producing novel coated nickel and/or cobalt superalloy bodies having increased resistance to oxidation, corrosion and thermal fatigue at high temperatures. The process comprises applying a thin layer of a platinum-group metal, siliciding and heating to an elevated temperature to diffuse and integrate the silicided platinum-group metal into the surface of the superalloy body. Then the superalloy body is exposed to a diffusion powder composition containing sources of aluminum or aluminum/chromium metals and heated in a hydrogen or inert gas atmosphere to an elevated temperature to codeposit and diffuse aluminum or aluminum and chromium into the silicided platinum-group metal-treated surface. Finally, the superalloy body is heated to its solvus temperature to form a ductile surface having an outer zone comprising a platinum-group metal aluminide, optionally ductilized by the solutioning therein of beta chromium. An inner stabilizing zone of silicon-rich phases is formed during said diffusion processes.

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N. Andover, MA, United States of America

Patrick R Lavery