In situ nanostructured (TiCr)CN coating by reactive plasma spraying

In situ nanostructured (TiCr)CN composite coating was prepared by reactive plasma spraying Ti-Cr-graphite powder under air atmosphere. The phase composition, microstructure, mechanical properties and wear performance were investigated. The results show that the coating consists of a mixture of TiN, Ti(CN), (TiCr)N, Cr, Ti3O, and amorphous graphite and CrN phases. The grain size is about 70 nm and the grains present equiaxed and columnar crystal morphologies. Moreover, 5 nm-sized nanocrystals are embedded in an amorphous phase. The (TiCr)CN composite coating possesses high hardness (1325 ± 120 HV) and toughness (4.35 ± 0.53 MPa m1/2). The friction coefficient and wear rate of the coating are 0.46 and 3.01 ± 0.17 × 10−6 mm3 N−1 m−1, respectively. The inclusion of metallic phase Cr could improve the toughness and wear resistance of the (TiCr)CN coating.