Nickel-5 Aluminum (95 % Nickel-5 % Aluminum) is widely used in the aircraft engine industry. The excellent adhesive and cohesive strength of the coating, oxidation resistance and machinability make it an ideal material as both a bond coat for subsequent topcoats and as a build up material for dimensional restoration of worn or mismachined components.
Plasma spraying has traditionally been the thermal spray process used to apply nickel aluminum, and the technical properties and performance characteristics are well documented. More recently, wire arc sprayed nickel aluminum is becoming widely used as an alternative to plasma spraying due to higher bond strengths, reproducibility, better machinability and more favorable economics.
This paper presents the results of a testing program designed to compare the technical properties of arc sprayed versus plasma sprayed Nickel-5 Aluminum coatings. Included are comparative bond strengths, hardness and metallurgy at coating thicknesses of .010″ to .060″on three substrate materials - 410 stainless, titanium and Inconel 718.
Additionally, comparative bond strengths and metallurgy of nickel aluminum as a bond coat for subsequent topcoats of aluminum, tungsten carbide, chromium carbide, alumina and magnesia zirconia are examined.
Spray processes tested include plasma spray, standard wire arc spray and high velocity wire Arc Jet.