Si含量对TiSixNy超硬涂层结构和性能的影响

In this study, a series of TiSixNy superhard coatings with different Si contents were prepared on Si(100) and M42 steel substrates using 2 Ti and 2 Si targets by reactive magnetron sputtering at 500℃. Their microstructure, phase configuration, mechanical behaviors and adhesion property were subsequently studied using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), microindenter and scratch tester. The results indicated that TiSixNy coatings were composed of nanocrystalline TiN, amorphous Si3N4 and a small amount of nanocrystalline TiSi2, Si content greatly affected microstructure, phase configuration, mechanical behaviors and adhesion property. Nitrogen-free TiN exhibited column structure, while incorporation of Si densified the microstructure of TiSixNy coatings. When Si content was low, the embedded nc-TiN had a preferred crystalline orientation of (111), increase of Si content made the preferred orientation from (111) to (200). A preferred orientation of (200) was followed when Si content was high. Both hardness and elastic modulus got to their maximum at the critical preferred orientation transformation. The scratch test revealed that adhesive force was gradually decreased with increase of Si content, a high adhesive force remained when the current of Si target was not larger than 2.0 A. Both values were decreased after formation of BN. Residual compressive stress value was successively decreased with increase of N content. Enhancement of hardness was attributed to formation of nanocomposite structure and solid solution hardening.