| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 92 === We applied plasma-sprayed technique of high cooling rate to obtain the coating with the property of the quite quick coagulation speed. Experimental results showed that we can’t get fully amorphous coating, the coating layer contains around 80% fraction of amorphous. Because of insufficient data for the microstructure, coagulation defects and particle erosion resistance of the Zr-based high entropy alloy coating, this study was to quantitate the non-crystallinity rate of the coating layer. Moreover, the correlation between bonding strength, microstructural defects and particle erosion characteristic of the coating was also investigated.
Although the coating layer contains around 80% fraction of amorphous, there still exists two crystalline phases, ZrO2 and Zr(Cr0.25Fe0.75)2, according to the XRD. In addition, SEM/BEI result the coating with quite amount of the coagulation defects arising with increasing coating thickness. The result of particle erosion experiment indicated that the increase in the coating thickness. This phenomenon is closely related to the increasing in spraying defects content of the coating, especially at high angle erosion. The material erosion behavior is the mainly wear mechanism of brittle cracks. At the low angle erosion, the coagulation defect effect reduced, therefore the particle erosion resistance obviously surpasses the high angle erosion sample.
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