Synthesis and properties of Cr–Al–Si–N films deposited by hybrid coating system with high power impulse magnetron sputtering (HIPIMS) and DC pulse sputtering

Abstract

The CrN and Cr–Al–Si–N films were deposited on Si wafer and SUS 304 substrates by a hybrid coating system with high power impulse magnetron sputtering (HIPIMS) and a DC pulse sputtering using Cr and AlSi targets under N2/Ar atmosphere. By varying the sputtering current of the AlSi target in the range of 0–2.5 A, both the Al and Si contents in the films increased gradually from 0 to 19.1% and 11.1% (mole fraction), respectively. The influences of the AlSi cathode DC pulse current on the microstructure, phase constituents, mechanical properties, and oxidation behaviors of the Cr–Al–Si–N films were investigated systematically. The results indicate that the as-deposited Cr–Al–Si–N films possess the typical nanocomposite structure, namely the face centered cubic (Cr,Al)N nano-crystallites are embedded in the amorphous Si3N4 matrix. With increasing the Al and Si contents, the hardness of the film first increases from 20.8 GPa for the CrN film to the peak value of 29.4 GPa for the Cr0.23Al0.14Si0.07N film, and then decreases gradually. In the meanwhile, the Cr0.23Al0.14Si0.07N film also possesses excellent high-temperature oxidation resistance that is much better than that of the CrN film at 900 or 1000 °C.