Structure engineering in vacuum-arc-deposited coatings of the MoN–CrN system

Abstract

The possibilities of structure engineering in multilayer coatings of the MoN–CrN system with relatively low heats of formation of component transition metal nitrides are demonstrated by varying pressure P_N of reactive gas (nitrogen) and negative bias voltage–U_s applied to a metal substrate. It is established that, by changing P_N from 7 × 10^–4 to 3 × 10^–3 Torr, it is possible to obtain coatings in two significantly different structural-phase states. A multilayer nonisostructural composite with hexagonal crystalline lattice in CrN layers and cubic type lattice in MoN layers is formed at low pressure, whereas an isostructural state with cubic lattice in both nitride layers is formed at high pressure. The existence of two types of structural states allows multilayer coatings with controlled hardness to be obtained, which reaches 38 GPa in the isostructural state.