Effect of Auxiliary Gas Flow Parameters on Microstructure and Properties of Ta Coatings Prepared by Three-Cathode Atmosphere Plasma Spraying

Abstract

Based on the three-cathode plasma spraying system, tantalum (Ta) coatings were prepared on the substrate of CuCrZr alloy. The effects of different auxiliary gas (helium) flow rates on the microstructure, phase composition, mechanical and wear resistance properties of Ta coatings were studied. The results showed that the oxidation degree of the coatings decreases first and then increases with the increase of the auxiliary gas flow. When the auxiliary gas flow rate is 70 L·min^–1, the oxidation degree of the coating is the lowest, minimum value of the porosity is 0.21%, and the bonding strength reaches the maximum, 59.3 MPa. At this time, the coating wear rate is 0.0012 mm³·N^–1·m^–1 with the best wear resistance. This indicates that the auxiliary gas flow has an important influence on the quality and surface mechanical properties of tantalum coating.

Keywords

plasma spraying / tantalum (Ta) coating / auxiliary gas flow rate / bonding strength / tribological property