Effect of C content on structure and the hardness of MoAlCN films

In this paper, Mo-Al-C-N films with different C content were deposited by magnetron sputtering. To investigate the effect of C content on the microstructure and hardness of Mo-Al-C-N films, surface morphology, composition, phase constituent and hardness of these films were characterized by field emission scan electron microscope, Energy Dispersive Spectroscopy, X-ray diffraction, Nanoindentor, respectively. Experiment results illustrate the diffraction peaks of Mo-Al-C-N films shift gradully toward lower angles due to the element C was dissolved into the Mo2N lattice by substituting N. The grain size decreases gradully from 35.8 to 16.7nm with the increase of C content in the range of 0−16at.% may be due to the amorphous CNx exited in the grain boundary. With increasing C content, the hardness of Mo-Al-C-N films increases firstly and reaches the maximum of 26 GPa at C content of 9 at.%, and then decreases to 21 GPa at C content 16 at.%.