Effect of Carrier Gas on Microstructure and Macroscopic Properties of Tantalum Coating Layer Manufactured by Kinetic Spray Process

초록

This study attempted to utilizing the kinetic spray process to manufacture tantalum coating layer and investigated the effect of carrier gas on the microstructure and macroscopic properties of the coating layer. The initial powder feed stock was a massive powder with an average particle size of 24.35 mu m and 99.99% purity. Tantalum coating layers were obtained utilizing kinetic spraying with two carrier gases, N-2 and He. The manufactured tantalum coating layers featured dense structures without impurities at alpha-Ta phase regardless of the carrier gas used. The hardness and porosity of the layers were found to be 285 Hv and 0.04% at the He coating layer, and 270 Hv and 0.28% at the N-2 coating layer. The measurement found that the coating layer produced with He gas had higher hardness and density than those of the coating layer produced with N-2 gas. Through observation of the manufactured layer microstructure, the coating layer using He gas showed a particle laminating maneuver caused by larger plastic deformation. It is possible that, compared to the case of using N-2 gas, higher particle speed can be applied when using He carrier gas to deposit tantalum powder. Based on observations above, this study also discussed possible methods to improve the physical properties of kinetic sprayed tantalum coating layer.

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