Effect of Content Ratio on Phase Composition and Hardness of （ZrTiAl）N Coatings

The hard reactive (ZrTiAl) N coatings were synthesized by multi arc ion plating on substrate of high speed steel. The influence of the content ratio of Zr, Ti and Al metal nitrides on the microstructures and surface hardness of (ZrTiAl) N coatings was investigated with X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and harness tester. The results show that the content ratio of Zr N, Ti N and Al N has a minor impact. For instance, weakly affected by a rather large changes in the metal nitrides content ratio, the as-deposited (ZrTiAl) N coatings, a solid solution type with fcc-phased grains preferentially grown in < 111 > orientation, displayed fairly high hardness and the lattice constant followed Vegard's law. When Ti N and Al N contents in (ZrTiAl) N coatings were as large as possible and nearly equal, the maximum hardness could be obtained.