ZrB₂-SiC粉末与等离子射流场的相互作用

In order to explore the reasons of loose structure and poor density of ZrB₂-SiC coating prepared by APS, the ZrB₂-SiC powder flying away from the jet field were collected by deionized water, and the microstructure and phase change of the powders before and after the plasma spheroidization were compared. The single particle deposition experiment was designed to investigate the melting state of the powders and the morphologies of the deformed particles, and the microstructure of the corresponding ZrB₂-SiC coating were detected combining with previous powder results. The results show that the ZrB₂-SiC powder in the plasma jet field reacts with the entrapped oxygen due to the "vortex effect", and the powder exhibits slight oxidation. The ZrB₂-SiC powder exhibits three morphological features: smooth surface, porous surface, and agglomerated surface after plasma spheroidization. The reasons are related to the unevenness temperature field of the plasma jet field and the flight paths of the powder. The deformed particles exhibit corresponding three topographical features: melted sufficient particles, agglomerated stacked particles, and semi-molten and semi-loose particles. The eutectic tends to form dense regions in the coating, while the agglomerated ZrB₂ and SiC particles are the main reasons for the formation of loose regions in the coating.