Mechanical properties of thin hard coatings on TiC-NiMo substrates

The present study focuses on TiC-based composites with Ni-Mo binders and thin coatings (TiN, (Ti, Al)N, TiCN, nc-(Al,Ti)N/a-Si(3)N(4)), produced by the Physical Vapor Deposition technique. The influence of two different Ni: Mo binder ratios (2:1 and 1:1) on the properties of the substrate and coating systems was evaluated. The effect of the substrate surface roughness on the overall substrate/coating system was also investigated. Nanocomposite nACo+ coatings showed the highest hardness value. In addition, these coatings also have lower modulus values, which makes them the best candidate for wear-resistant applications. TiCN coatings have the second highest hardness value, but due to poor adhesion qualities, especially at higher roughness values, delamination was found to be present even directly after the coating process without any load. This is assumed to be related to the higher inherent residual stresses of TiCN coatings with TiC NiMo cermets.