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

CrN and CrAlN films were deposited on WC-Co, Si wafer and SUS 304 substrates by a hybrid coating system with high power impulse magnetron sputtering (HIPIMS) and pulsed DC sputtering. By varying the sputtering power of the Al target in the range of 0 A to 2.5 A, the Al content in the films increased from 0 to 17.7%. The effect of the Al content on the phase structure, mechanical properties and oxidation behavior of the films was investigated. The results indicated that the as-deposited CrAlN films possess the FCC structure of (Cr, Al)N phase. The hardness increased from 20.8 GPa for the CrN film to peak value of 25.4 GPa for the Cr0.28Al0.14N film and decreased with further increasing the Al content. The films with different Al content exhibited similar friction coefficients and wear behavior. The high-temperature oxidation resistance of the Cr0.28Al0.14N film was much better than that of the CrN film at 900-1000 degrees C.