Thermal stability and effect of substrate temperature of TiSiBC hard nanocomposite coatings on microstructure, mechanical, thermal behaviour deposited by magnetron sputtering

The TiSiBC nanocomposite thin films deposited on steel (SS 304) at different substrate temperatures have been investigated. TEM analysis showed that film morphology consist of very fine grain size in the range of 10 nm. With the increase of substrate temperature the crystallinity of the film was also increased. At 500 °C substrate temperature other crystalline phase containing Ti and Si also appear along with the TiB2. The optimum temperatures were around 400–450 °C, where the film had higher hardness and modulus, further increase of temperature led to decrease in the hardness and modulus, which is due to formation of softer phases. The film deposited at 400 °C was smooth with the average engineering roughness of about 11 nm. The nanocomposite film was thermally stable in air up to 900 °C with little decrease in hardness.