The structure and properties of ZrAl(Y)N coatings deposited at various N2/Ar flow ratios

Abstract

ZrAl(Y)N coatings were deposited on cemented carbide (YG8) and silicon (100) substrates by plasma-enhanced medium frequency reactive magnetron sputtering technique. The effects of yttrium addition and N2/Ar flow ratios on the composition, microstructure, mechanical properties, and oxidation resistance of ZrAl(Y)N coatings were characterized by scanning electron microscopy, X-ray diffraction and nano-indentation tests. The result shows that, with yttrium added to ZrAlN coating, the intensity of (111) peak apparently decreases and thus the preferred orientation changes to (200). The hardness and H3/E2 increase by adding yttrium to the ZrAlN coating. The oxidation resistance of the ZrAlN coating is dramatically improved via yttrium addition. With the increase of N2/Ar flow ratio, the orientation of ZrAl(Y)N coatings changes and the crystallinity gradually lowers. The deposition rate continuously decreases with N2/Ar flow ratio increasing. Both the hardness and H3/E2 of ZrAl(Y)N coatings are enhanced by increasing N2/Ar flow ratio. When N2/Ar flow ratio increases to 0.5, the hardness and H3/E2 get the maximum values at 31.1GPa and 0.178GPa respectively. However, the oxidation resistance of ZrAl(Y)N coatings deteriorates slightly with N2/Ar flow ratio increasing.