A hard yet tough CrAlSiN nanocomposite coating for blades deposited by filtered cathode vacuum arc

Abstract Hard yet tough nanocomposite coatings with simultaneously high plastic deformation resistance and elastic deformation recovery capacity represent a new class of compressor protective coatings, which are vital for its serviceability in high sand dust environments due to the blocking effect of nanocrystalline amorphous structure on dislocation and crack. In this work, a set of CrAlSiN (nc-(Cr,Al)N/a-Si3N4) nanocomposite coatings was deposited by the filtered cathodic vacuum arc under various nitrogen fluxes. The as-deposited coatings exhibited refined grain size, well-defined nanocrystalline/amorphous phase separation, and highly dense architecture. These features allowed the achievement of the increased properties in terms of high hardness (H = 40.4 GPa) and toughness (H/E* = 0.095, H3/E*2 = 0.367) when the nitrogen flux was 100 sccm. Hard yet tough CrAlSiN nanocomposite coating showed excellent scratch response and tribological properties by enhanced cooperative deformability through increased H, H/E*, and H3/E*2, local epitaxial growth at interface and annihilation of crack and dislocation multiplication sources in grain boundaries to reduce crack initiation and propagation, and adhesion failure.