A novel method for in-situ synthesized TiN coatings by plasma spray-physical vapor deposition

As a novel process, the plasma spray-physical vapor deposition technology was used to in-situ synthesize the TiN coatings on the Ti-6Al-4V alloy. Due to its high power input and very low pressure, relatively pure TiN coatings with hybrid structures were successfully obtained at different spraying distances, which was not previously achieved with other thermal spraying processes. The results showed that the nitriding reaction occurred not only in the plasma jet but also on the substrate. Moreover, the spraying distance was found to affect the phase, microstructure, and mechanical property of the TiN coating. As a result, the mechanical properties of the Ti-6Al-4V alloy can be significantly enhanced by the TiN coatings.