EFFECT OF PLASMA SPRAYING PARAMETERS ON THE PROPERTIES OF (Ti, Cr)C–Ni COMPOSITE COATINGS

Abstract

The effect of plasma spraying parameters on the adhesion and porosity of metal ceramic coatings from clad (Ti, Cr)C–Ni composite powders was studied. The coatings were produced by atmospheric plasma spraying (APS) using a mixture of argon and hydrogen as plasma gases. The arc voltage and current were chosen as variable parameters for controlling the spraying distance and argon flow rate. The 40–80 μm (Ti, Cr)C-based composite powders clad with 17, 25, and 33% Ni were used to produce the plasma coatings. The microstructure, porosity, and adhesion of the coatings were studied to assess their quality. Optimal plasma spraying modes were determined for each powder. Plasma spraying should be conducted at an electric arc power of 27–29 kW. Increase in the power caused the nickel layer on the (Ti, Cr)C particles to evaporate and degrade, resulting in reduced coating uniformity, increased porosity, and decreased adhesion. The density and adhesive strength of the coatings improved as nickel content of the (Ti, Cr)C–Ni composite power increased from 17 to 33 wt.%.  It was found that 17 wt.% Ni in the (Ti, Cr)C–Ni composite powders was not sufficient for producing high-quality plasma coatings. The (Ti, Cr) C–33% Ni coating had the highest adhesion (38 ± 1.5 МРа) and lowest porosity (7–8%).