Characterization and properties of titanium nitride coatings deposited by Very Low Pressure Reactive Plasma-Spraying

Characterization and properties of titanium nitride coatings deposited by Very Low Pressure Reactive Plasma-Spraying Abstract The objective of this work is to investigate the microstructure, composition and mechanical properties of titanium nitride coatings manufactured by reactive Very Low Pressure Plasma Spraying (R-VLPPS) process. Pure titanium powder is injected in the plasma and a reactive gas is added to generate a reaction with the molten particles /vapors. Firstly the plasma-jet properties were analyzed by means of optical emission spectroscopy (OES). Then titanium nitride coatings were manufactured with a F4-VB low-power plasma gun under a working pressure of 150 Pa. Investigations show that according the spraying distance or the radial position of the substrates compared to the plasma jet axis, the resulting coatings microstructures are different (mix of molten or unmelted particles). In addition, the coatings composition is modified with an evolution of TiN0.3 and TiN phase crystalline phases. Finally, the mechanical properties of the coating were examined such as hardness, friction, wear and fracture toughness. Keywords: very low pressure reactive plasma spraying, titanium nitride coating, microstructure, composition, mechanical properties