Comparison study of the microstructure, mechanical and tribological properties of TiAlN, AlCrBN and TiAlN/AlCrBN coatings by cathodic arc evaporation

TiAlN, AlCrBN andTiAlN/AlCrBN coatings were deposited on cemented carbide by cathodic arc evaporation. SEM, TEM, XRD, nano-indentation test, Vickers indentation test, Rockwell indentation test and ball-on-disk tribological test were employed to characterize the microstructure, mechanical and tribological properties of the coatings. The results revealed that different from the fine columnar structure of TiAlN coating, AlCrBN coating exhibited an elliptical structure with grains sizes down to 5 nm.TiAlN/AlCrBN coating with approximately 24 nm thick modulation period demonstrated a polycrystalline structure consisting of fcc-(Al, Ti, Cr)N solid solution with (111) and (200) preferred orientation. The AlCrBN coating exhibited better wear resistance than TiAlN and TiAlN/AlCrBN coatings at room temperature due to its high fracture toughness and H/E. At room temperature, the wear mechanism of the three coatings was mainly abrasive wear. However, the main wear mechanism of TiAlN and TiAlN/AlCrBN coatings at 700 degrees C temperature transformed into obvious adhesive wear. TiAlN/AlCrBN coating exhibited excellent high-temperature oxidation resistance and stability due to the effect of interlayer interfaces, significantly reducing oxidation and adhesion phenomena under high-temperature wear conditions. Therefore, the main wear mechanism of TiAlN/AlCrBN coating still manifested as abrasive wear.