Effects of plasma spraying process on microstructure and mechanical properties of Cr₂AlC/410 composite coatings

To investigate the influences of Cr₂AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr₂AlC reinforced 410 stainless steel composite coatings, the coatings containing different mass fractions of Cr₂AlC were prepared and investigated. The composite coating exhibited low porosity and high adhesion strength. The addition of Cr₂AlC significantly enhanced the hardness of the composite coatings through particle strengthening. However, when the mass fraction of Cr₂AlC was 20%, the aggregation of Cr₂AlC resulted in a strong decrease in the coating preparation efficiency, as well as a decline in adhesion strength. In the supersonic plasma spraying process, the Ar flow rate mainly influenced the flight velocity of the particles, while the H₂ flow rate and the current mainly affected the temperature of the plasma torch. Consequently, all of them influenced the melting degree of particles and the quality of the coating. The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min, the H₂ flow rate is 25 L/min, and the current is 385 A.