Influence of Si Content on Structure and Properties of CrSiN Coatings

Objective To prepare the CrSiN coatings with different Si contents through controlling Si target power using physical vapor deposition (PVD) magnetron sputtering method at room temperature so as to explore the influence of Si content on structure and properties of coating. Methods The structure, hardness, toughness and wear resistance of CrSiN coating were respectively evaluated by X-ray diffraction, energy dispersive spectroscopy testing, nanoindentation test, Vickers indentation and friction test. And the indentation morphology was analyzed further by scanning electron microscope. Results The results indicated that all coatings showed (111), (200) orientation of the NaCl structure. With increasing Si content, XRD peak turned wider and the grain refinement effect was obvious. With adding Si element, the hardness, modulus and toughness increased firstly and then decreased. Compared to CrN coating, the hardness increased from 21.4 GPa to 35.7 GPa, modulus improved from 337.7 GPa to 383.9 GPa and plasticity index increased to 0.55 from 0.5, achieving an integration of hard and tough for CrSiN coating with Si content at 3.2%. The wear resistance of CrSiN coating was improved by almost an order of magnitude and the wear rate was the lowest (1.0*10~(-17) m~3/(N·m)) when Si content was 3.2%. Conclusion The structure can be obviously improved, and the hardness, toughness and wear resistance can be increased by adding silicon in CrSiN coating. However, the amount of Si element needs to be added appropriately for performance optimization.