Microstructures of (Ti,Cr,Al,Si)N films synthesized by cathodic arc method

(Ti,Cr,Al,Si)N films were deposited on WC and Si substrate by cathodic arc method with TiCrAlSi alloy cathodes. At lower (Al + Si) contents from 0.56 to 0.60, the crystal structure of (Ti,Cr,Al,Si)N had NaCl type cubic structure. With increasing (Al + Si) contents, the NaCl structure changed to a hexagonal structure. The maximum hardness of (Ti,Cr,Al,Si)N was 31 GPa at 0.56 of (Si + Al) contents. Corresponding with structural changes from NaCl to wurtzite, microhardness decreased down to 26 GPa. TEM photographs indicated that embedding Si atom was effective to decreased grain sizes of 5-10 nm. In this paper, relationships between microstructure and microhardness as a function of Si and Al contents are discussed based on the phase transformation, analyzed by X-ray diffraction method and transmission electron microscopy.