Investigation on oxidation behaviors of Ti-Si-N coating at high temperature

Purpose Ti-Si-N coating with nanocomposite structure is a promising protective coating for cutting tools which will be subject to high temperature oxidation during service. This study aims to investigate the thermal stability of Ti-Si-N coatings and lays the foundation for its application in high speed dry cutting. Design/methodology/approach Nanocomposite Ti-Si-N coating was deposited on stainless substrate and silicon wafer (100) by Ti90Si10 alloy target by using cathodic arc ion plating. The microstructure of Ti-Si-N coating had been detected by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Findings The results suggested that the coating was TiN nanocrystals with a diameter of 6.3 nm surrounded by amorphous Si3N4. The oxidation test was conducted under 550, 650, 750, 800, 850, 900 and 950 degrees C for 2 h. The structure evolution was observed by Scanning electron microscope (SEM), energy dispersive spectrum (EDS), XRD and XPS. The results indicated that rutile has been formed at 650 degrees C, while Si3N4 began to oxidized at 800 degrees C. The grain size of TiN increased from 6.3 to 13 nm as the samples oxidized from 550 to 800. Micro-crack also formed in samples oxidized over 900 degrees C. Originality/value Ti-Si-N coating, in this study, was deposited by cathodic arc ion plating using alloy target at high-bias voltage. The oxidation temperature ranged from 500 to 950 degrees C with TiN coating as reference.