Influence of oxidation on the structural and mechanical properties of TiAlSiN coatings synthesized by multi-plasma immersion ion implantation and deposition

TiAlSiN nanocomposite and TiN coatings were synthesized by multi-plasma immersion ion implantation and deposition. The structure, hardness and tribological properties of both coatings oxidized at 800 °C were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, nano-indentation and ball-on-disk tests. The results show that the TiN coating was oxidized almost completely after air exposure at 800 °C. Except for a thin oxidized layer formed on the top surface containing TiO2, Al2O3 and SiO2, the cross section of the TiAlSiN coating remained in its original configuration after oxidation. Analysis revealed that the oxidized layer remained in a similar structure as before oxidation, which is TiO2 nanocrystals embedded in an amorphous SiO2 matrix. The hardness results show that the TiAlSiN coating after oxidation maintained a similar hardness as the un-oxidized coating. In addition, the TiAlSiN coating also showed a high wear resistance at 800 °C.