Microstructure and Tribological Properties of Cathodic Arc Ion Plated TiAlN and TiSiN Coatings at High Temperatures

Abstract

TiAlN and TiSiN coatings were deposited on YT15 cemented carbide using a cathodic arc ion plating (CAIP). The surface-cross section morphologies, chemical elements, surface roughness, phases, and chemical valences of as-obtained coatings were analyzed using a scanning electron microscopy (SEM), energy dispersive spectroscopy, atomic force microscopy (AFM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS), respectively, and the bonding strength, hardness and Young's modulus of TiAlN and TiSiN coatings were measured using a scratch tester and nano-indentation, respectively, and the wear mechanism at high temperatures was also discussed. The results show that the surface roughness of TiAlN and TiSiN coatings is 69.1 and 58.0 nm, respectively, and the corresponding average particle size is 998.8 and 817.2 nm, respectively. The TiAlN coating is composed of TiAlN and AlN, while the TiSiN coating is composed of TiN and Si3N4. The bonding strength of TiAlN and TiSiN coatings is 84.3 and 72.6 N, respectively, the hardness and Young's modulus of TiAlN coating is 23.67 and 415.80 GPa, respectively, while that of TiSiN coating is 20.46 and 350.40 GPa, respectively. The average coefficients of friction (COFs) of TiAlN and TiSiN coatings are 0.4516 and 0.4807, respectively; the corresponding wear rate is 589.7 × 10−6 and 4142.2 × 10−6 mm3 N−1 s−1, respectively; the wear mechanism of TiAlN and TiSiN coatings is oxidation wear and abrasive wear.