EFFECT OF COMPOSITION AND MECHANICAL PREPARATION METHOD OF A COMPOSITE TiC-Ni MIXTURE ON TITANIUM CARBIDE CONTENT IN COATINGS FORMED BY COLD SPRAYING

This paper describes how the method of preparing a composite TiC-nNi mixture (n = 40, 50, and 75% are the volume fractions of nickel) affects the carbide content in the coating material obtained by cold spraying. It is shown that, when coatings are obtained from a powder mixture prepared in a V-shaped mixer, the titanium carbide content is lower than in coatings obtained from powders mechanically processed in a high-energy planetary mill. In the case where the powder mixture is mixed in a V-shaped mixer, fine titanium carbide particles do not reach the substrate surface during spraying because they are decelerated in a shock-compressed gas layer when a supersonic jet flows on an obstacle. Thus, these particles do not participate in the formation of the coating. Spraying a mechanically treated powder consisting of composite agglomerated TiC-Ni particles allows for a significant (approximately 1.8-fold) increase in the carbide content in the coating.