Substrate effect in the evaluation of elastic modulus of thin PVD coatings from nanoindentation

Abstract

The comparison of nanoindentation results on reactive HiTUS TiZrHf+ME-N_y (ME = Nb, V, Ta and VNbTa) and reactive DCMS NbMoTaW coatings showed that the influence of substrate stiffness is still not fully eliminated in the evaluation of indentation modulus. To obtain comparable results by keeping the systematic error resulting from the existing evaluation procedures the same, nanoindentation should be performed using the same test parameters, a method for depth profile acquisition, a data evaluation procedure, and coatings with similar thicknesses on the same type of substrate. Applying these rules to nanoindentation on TiZrHf+ME-N_y coatings showed that the addition of ME = Nb, V, Ta, and VNbTa caused some degradation of mechanical properties indicating negligible or even negative “cocktail effect”.