Hardness and Young's modulus of nanoporous EB-PVD YSZ coatings by nanoindentation

A nanoindentation technique for determining hardness and Young's moduli is applied to electron beam-physical vapor deposition (EB-PVD) ZrO2-4 mol%Y2O3 coatings. The porosity of the coatings increased with increasing substrate rotation speed during deposition. The hardness and Young's modulus showed a significant dependence on the substrate rotation speed and measurements made on columnar structures were strongly anisotropic. The hardness and Young's modulus of the surface regions of the coatings is found to be higher than that of the side regions. The hardness and Young's moduli of the surface regions of the coatings have a nearly constant value of approximately 10 GPa and 230-250 GPa, respectively, whereas those of the side areas decreased with increasing substrate rotation speed.