Understanding the relationship between microstructure and mechanical behavior of plasma-sprayed amorphous Al2O3–YAG ceramic coating based on depth-sensing indentation measurements

Yang, Kai; Ai, Yizhaotong; Qiang, Linya; Zhang, Xiaozhen; Zhuang, Yin; Sheng, Jing; Ni, Jinxing; Ding, Chuanxian

Understanding the relationship between microstructure and mechanical behavior of plasma-sprayed amorphous Al2O3–YAG ceramic coating based on depth-sensing indentation measurements

2022

Based on depth-sensing indentation measurements, the relationship between microstructure and mechanical behavior of plasma-sprayed amorphous Al₂O₃–YAG ceramic coating was investigated. The Al₂O₃ and Al₂O₃–Y₂O₃ coatings were also deposited for performance comparison and mechanism discussion. In nanoindentation tests, the load-control mode was selected. Constant loading rate/load (P′/P) method was applied to obtain the steady-state indentation process by control loading. Scanning electron microscope, electron backscatter diffraction, depth-sensing indentation method of Oliver and Pharr, Weertman–Dorn equation and elastic–viscoelastic–viscous (EVEV) model were combined to analyze microstructural features, phase distribution and nanomechanical behavior of the coatings. The results revealed that amorphous Al₂O₃–YAG coating possessed excellent microstructure/mechanical performance uniformity, larger recovery resistance Rₛ, higher fraction of energy dissipation rd and better creep performance. Compared with the Al₂O₃ and Al₂O₃–Y₂O₃ coatings, the Al₂O₃–YAG coating showed a significant increase in creep compliance, which denoted corresponding decrease in coating elastic modulus and reflected more pronounced relaxation phenomenon.

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