Effect of TiO2 on mechanical and thermal properties of Al2O3-based coating via atmospheric plasma spraying

In this study, Al2O3-based coatings with varying TiO2 contents (0, 3, 13, and 40%) were fabricated using atmospheric plasma spraying technique. To compare the superiority of the samples, their mechanical (Vickers hardness and adhesion strength) and thermal properties (thermal conductivity and thermal shock resistance) were characterized. As observed, Al2O3-40%TiO2 (A-40T) coating exhibited relatively inferior mechanical properties but superior thermal insulation and thermal shock resistance at 600 degrees C. According to the microstructure and phase analysis, this finding is attributed to the special phase, Al2TiO5, and preexisting microcracks inside the coating. Thus, A-40T manifested excellent characteristics for thermal insulation application compared with pure Al2O3 and low-TiO2 content coatings.

Automated summary

In this study, Al2O3-based coatings with different TiO2 contents were fabricated using atmospheric plasma spraying technique. The samples were characterized for their mechanical and thermal properties. The Al2O3-40%TiO2 (A-40T) coating showed relatively inferior mechanical properties but superior thermal insulation and thermal shock resistance at 600℃. The special phase Al2TiO5 and preexisting microcracks inside the coating contributed to this finding. A-40T exhibited excellent characteristics for thermal insulation application compared with pure Al2O3 and low-TiO2 content coatings.