Microstructure, mechanical and high-temperature tribological properties of amorphous SiC films by pulsed magnetron sputtering

a-SiC thin films were deposited using pulsed magnetron sputtering by tuning substrate bias voltages. With the increase of bias voltages to-150 V, the microstructure transforms from columnar to featureless, and the surface changes from cauliflower-like to smooth and then to hole. The density of the Si-C bond and content of sp3 C-C first increase and then decrease and reach a maximum value at-100 V. The internal stress, adhesion strength, hardness (H) and elastic modulus (E) also increase and then decrease due to the changes in structures. The maximal internal stress, adhesion strength, H and E are 1.54 GPa, 6.68 N, 21 GPa, and 230 GPa, respectively. The film deposited at-100 V exhibits good tribological performance from 25 degrees degrees C to 600 degrees degrees C. The wear mechanism of the films at elevated temperatures was discussed in detail.