Reactive nitrogen plasma spray coating of titanium nitride: plasma torch design and coating analysis

In this paper, a thermal DC plasma torch was designed and developed for plasma spraying of a titanium nitride layer. Thermal plasma spray torch is a kind of non-transferred torch which can produce a high energy and high temperature plasma arc jet. Ti powders were injected into the plasma jet interacted with nitrogen plasma, resulted in a thick and hard layer of titanium nitride. Coating sample produced by this method was analysed with Raman spectroscopy confirming titanium nitride production. To study the thickness of the layer optical microscopy was used. It was found that the resulted layer is thicker than the layer synthesized by other deposition methods and it mainly consists of pure titanium nitride.