Application of Nanoindentation Technique to Characterization of Anisotropy of Detonation Sprayed Al₂O₃/3%TiO₂ Coatings

The microstructure and indentation load-displacement behavior of sprayed Al2O3/3%TiO2 coating were investigated.In comparison with the surface of the coating,the cross-section of the coating had more pores with bigger size and more unhomogeneous distribution.The anisotropic microstructure of the coating led to apparently anisotropic mechanical properites such as plasticity,elasticity,hardness and Youngs modulus.However,the surface of the coating had better ability to resist applied load and better elastic recovery after unloading than the cross-section.The hardness and Youngs modulus of the surface of the coating were 10.3 GPa and 170.7 GPa,respectively.While those of the cross-section of the coating were 2.9 GPa and 234.5 GPa.