Structure and hardness of vacuum arc deposited multi-component nitride coatings of Ti, Zr and Nb

Ternary transition-metal nitride coatings of(Ti,Zr)N, (Ti,Nb)N and (Zr,Nb)N were deposited using a triple cathode vacuum are deposition system by simultaneously operating two cathodes of the appropriate metals in a low-pressure nitrogen background. The magnetically collimated plasma flux distribution was measured using a 13-element ion saturation current probe. The microstructure, composition, and hardness of the coatings were determined using X-ray diffraction, Auger electron spectroscopy, and Vickers indentation, respectively. The plasma flux distribution had two peaks whose relative positions were related to the two cathodes. Coatings applied to extended substrates had a compositional gradient. In almost all cases, the ternary nitrides had a single-phase solid-solution microstructure, whose lattice constants had values intermediate between those of the parent binary nitrides. The ternary coatings were considerably harder than either of the parent binary nitrides. (Ti,Nb)N had the highest microhardness: similar to 50 GPa. (C) 2000 Elsevier Science S.A. All rights reserved.