High-power-density sputtering of industrial-scale targets: Case study of (Al,Cr)N

Large-scale sputter-deposition of hard protective coatings has not been prevalent as the large dimensions of the industrial targets posed an enormous technological challenge: only relatively low power (and plasma) densities could be achieved, resulting ultimately in poor performance of such coatings. Here, we introduce a novel sputtering technology allowing to reach high power densities for industrial tubular targets. This is realised on the principle of a longitudinal movement of a reduced-size magnetron inside the target. In doing so, peak power densities of 840 W/cm2 have been achieved for the overall power of 25 kW and the target dimensions of Ø110 × 510 mm. To demonstrate the effectiveness of the solution, we produced a series of cubic (Al,Cr)N coatings by sputtering an Al60Cr40 target. Most of the coatings have a stoichiometric composition, smooth surface and a moderate amount of growth defects. Significant improvements through recipe optimisation could be achieved resulting in mechanical properties (hardness, fracture toughness, wear resistance) being equal to and even exceeding those of the benchmark coatings produced by means of conventional sputtering and cathodic arc evaporation. Our results open up great potential of this novel sputtering technique for the coating industry.