TEM characterization of the TiN coatings fabricated by reactive plasma spraying

The nanostructured TiN coatings were fabricated by the reactive plasma spraying, and the micro-structure of the coatings was analyzed by XRD, SEM and TEM. The results show that the coatings are composed of TiN and Ti3O phases, and the coatings have the typical sprayed lamellae structures. The nanoscale grains with particle diameters less than 100 nm are observed in the coatings by TEM, and both fine equiaxed and columnar grains are found simultaneously in the nanostructured TiN coatings. Furthermore, the deformation twins are verified by TEM in the coatings, which are caused by the high cooling rate and the non-uniform temperature distribution in the plasma jet.