Nitride films deposited from an equimolar Al–Cr–Mo–Si–Ti alloy target by reactive direct current magnetron sputtering

Films are deposited from a single Al20Cr20Mo20Si21Ti19 alloy target in various argon/nitrogen atmospheres by direct current magnetron sputtering. Two sets of substrate parameters are examined; one with a substrate temperature of 300 K and the substrate grounded (U0 V, 300 K), and the other with the substrate biased at − 50 V and its temperature maintained at 573 K (U− 50 V, 573 K). The films produced in pure argon or at lower nitrogen flow rates are amorphous, regardless of the substrate parameters. At higher nitrogen flow rates, however, all of the coatings are found to form an FCC (face-center-cubic) NaCl-type structure. Although this coating system contains several well known immiscible nitrides, i.e. TiN, AlN and Si3N4, it is determined that only a single FCC phase forms, namely a single FCC (AlCrMoSiTi)N solid solution, regardless of the deposition conditions. The lower deposition rate and reduced surface roughness of the U− 50 V, 573 K films compared to the U0 V, 300 K films are considered to result from the increased densification and resputtering of coating material. The majority of the coatings are found to have hardnesses of only 10 to 16 GPa. The highest hardnesses of 25 and 22 GPa are obtained for the crystalline nitride U− 50 V, 573 K coatings deposited at N2/(Ar + N2) ratios of 50 and 67%, respectively. More in depth explanations behind the structure and properties of these multi-element films are presented within the paper.