Thermal shock resistance of Al2O3 and Al2O3-13%TiO2 coatings deposited by supersonic atmospheric plasma spraying

Abstract

The thermal shock resistance of FeAl/Al2O3, FeCrAl/Al2O3, FeAl/Al2O3-13%TiO2, and FeCrAl/Al2O3-13%TiO2 coatings deposited by supersonic atmospheric plasma spraying (SAPS) on the stainless steel matrix was investigated in this paper. The microstructure of the coatings was characterized by scanning electron microscope, the porosity was measured by image analysis, the mass fraction of α-Al2O3 was calculated by multi peak method, and the bonding strength was tested. The results show that, the mass fraction of α-Al2O3 in Al2O3 coating is 40.3%~42.5%, the porosity is 3.47%~3.52%; the mass fraction of α-Al2O3 in Al2O3-13%TiO2 coating is about 24.0%~29.7%, the porosity is 3.12%~3.31%. The results of water-quenching tests at 800 ℃ for 30 min show that, the FeCrAl/Al2O3 coating presents the highest thermal shock resistance, and the FeCrAl/Al2O3-13%TiO2 coating takes the second place. The FeAl/Al2O3 and FeAl/Al2O3-13%TiO2 coatings exhibite the same thermal shock resistance, which are the worst in four kinds of coatings.

Keywords

• supersonic atmospheric plasma spraying
• hermal shock resistance
• coatings
• al2o3
• feal
• fecral