Low-temperature deposition and hardness enhancement of α-(Al,Cr)2O3 films by reactive high power pulsed magnetron sputtering

Abstract

This paper offers a method to grow corundum structure thin films of α-(Al,Cr)2O3 in a High Power Pulsed Magnetron Sputtering (HPPMS) system. The films were characterized by grazing incidence x-ray diffraction (GIXRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and nanoindentation. The results indicate that stoichiometric α-(Al,Cr)2O3 film could be deposited at 540 °C without the formation of other metastable phases. The stable process of the magnetron sputtering ensures the smooth and compact surface of the film composed of nano-scale particles. The Cr in films can induce the formation of solid solution and enhance the mechanical property of the films. The hardness of the α-(Al,Cr)2O3 was calculated as ∼25.6 GPa, which is much higher than that of the film deposited using the Al target. These results are considered have positive effect on the low-cost depositing α-phase alumina films on high speed steel substrates as cutting tools.