Synthesis of TiN coatings by high power pulsed magnetron sputtering and its mechanical properties

The TiN thin films were deposited by high power pulsed magnetron sputtering(HPPMS) on substrates of high-speed steel. The influence of the deposition conditions, including but not limited to the pulsed current, ratio of N₂ and Ar flow-rates, and substrate temperature, on the microstructures and mechanical properties of the TiN coatings were investigated with X-ray diffraction, scanning electron microscopy and conventional mechanical probes. The results show that depending significantly on the pulsed current, the TiN coatings improved the mechanical behavior of the substrates, such as the nano-hardness, Young's modulus, wear-resistance, friction coefficient and interfacial adhesion. To be specific, as the pulsed current increased, both the hardness and Young;s modulus changed in an increase-decrease mode;the growth-rate and compactness increased. Grown at 20 A, the strongest surface hardness and interfacial adhesion of the TiN coatings, with (111) preferential growth orientation, were 25 GPa and 70 N, respectively.