Microstructure and mechanical properties of Cr films deposited with different peak powers by high-power impulse magnetron sputtering

For high-power impulse magnetron sputtering (HIPIMS), the peak power applied to the target is of great importance for regulating the ionization degree of the metal target and ion/atom flux ratio. In this work, chromium (Cr) films were deposited on 316-L stainless steel substrates and silicon (100) wafers with different peak powers by HIPIMS. The relationship between peak target power and properties of Cr films was explored in detail. The resulting structure and mechanical properties of deposited Cr films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), atomic force microscopy (AFM), indentation hardness and scratch tester. The results indicate that the ionization degree of metal target and ion/atom flux ratio increase with the increase in peak power but without the loss of deposition rate at the same time. At low ionization degree, the deposited Cr film has low compressive residual stress and low hardness but good adhesion strength. When the ionization degree of target metal increases with increasing peak power, Cr film exhibits finer size and smoother surface with improved hardness but decreased adhesion strength.