Effect of nitrogen flow rate on the microstructure, mechanical and tribological properties of CrAlTiN coatings prepared by arc ion plating.

The influence of the nitrogen flow rate on the microstructure, mechanical and tribological properties of the CrAlTiN coatings prepared by arc ion plating technology was systematically investigated. The results showed that the content of N and Ti increased, while the deposition rate and grain size decreased with the nitrogen flow rate from 100 sccm increased to 500 sccm. The toughness and adhesion strength firstly increased and then decreased. The coatings showed a cubic NaCl structure, (111) and (200) crystal planes show competition growth, while high nitrogen flow promoted the growth of (200) plane. The main wear mechanisms of CrAlTiN coating against Si 3 N 4 ball were adhesive and chemical erosion. The coefficient of friction decreased with the increase of nitrogen flow rate, but the wear rate firstly decreased and then increased, the coating prepared by using 500 sccm nitrogen flow appeared to peel off the substrate. In addition, the shear resistance and contact area were reduced due to the adhesive Cr–O, Al–O and Ti–O with a low coefficient of friction and high hardness. Therefore, a low coefficient of friction of the coating was obtained. As a result, the CrAlTiN coating prepared by applying optimal nitrogen flow rate had excellent mechanical and tribological performance. • The research revealed that the content of nitrogen has significant effect on the microstructure and properties of CrAlTiN coating. • High nitrogen flow promoted the growth of (200) plane. • In addition, the shear resistance and contact area were reduced due to the adhesive Cr–O, Al–O and Ti–O composition with low coefficient of friction and high hardness. [ABSTRACT FROM AUTHOR]