Wear Properties of Al_2O_3 wt percent TiO_2 Coatings Plasma-Sprayed Using Nanocrystallian Powders

摘要

Correlation between microstructure and wear resistance of Al_2O_3-8 wt. percent TiO_2 coatings plasm-sprayed using nanopowders was investigated in this study. Four types of nanostructured Al_2O_3-8 wt. percent TiO_2 powders were plasma-sprayed on a low-carbon steel substrate by using different critical plasma spray parameters (CPSP). The coatings consisted of completely melted region of gamma-Al_2O_3 phase and partially melted region of alpha-Al_2O_3. The fraction of the partially melted regions and pores decreased with increasing CPSP. The hardness and wear test results revealed that the hardness of the coatings increased with increasing CPSP, while the wear resistance was the highest for the coating sprayed with the lowest CPSP. The main wear mechanism was a delamination mode in the coating sprayed with the high CPSP, but was changed to an abrasive mode in the coating sprayed with the low CPSP. According to this change in the wear mechanism, the wear resistance was the best in the coating sprayed with lowest CPSP.