Effect of densification distribution on the Young's modulus of porous coatings after nano-indentation

Nano-indentation of a porous ceramic coating leads to crushing and densification of the coating under the indenter. In this work, finite element simulations of indentation on the porous coating have been carried out to study the effect of the size and distribution of densification on Young's modulus measured by nano-indentation. Two totally different distribution patterns have been simulated in this work. In the case of gradient densification, the Young's modulus increased by 8.6% when the densification has occurred in the maximum influenced area. While the Young's modulus increased by 2% with a uniformed densification. Examinations of the cross-section of the coatings have suggested that the densification after the indentation is close to the second model. The measured Young's modulus could have differed by 2%. The effect of densification on the Young's modulus measured by using nano-indentation is strongly dependent on the densification patterns of the porous coating.