Enhanced of Nano-mechanical Properties of NiTi Alloy by Applied Nanostructured Tantalum Nitride Coating with Magnetron Sputtering method

    Nowadays, suitable protective properties of tantalum nitride coatings, such as hardness, abrasion resistance and high corrosion resistance lead to increasing its application in medical engineering and improving the biological behavior of titanium and its alloys. In this research, nanostructured tantalum nitride coating was applied on the NiTi alloy by magnetron sputtering method. Then, the phase, structural and morphological properties of coating were investigated by using XPS, FESEM, AFM, respectively, as well as the nanomechanical properties of the coating were evaluated by using Nano-scanning and nano-scratch methods in different loads.     The results indicate that applying the uniform, homogeneous and crack free tantalum nitride coating with a thickness of 1050 nm. The hardness and elastic modulus of coating is 12.6 and 87.4 GPa under the applied force of 1000 μm and the penetration depth of 91 nm, respectively, which resulted in enhancing the hardness of NiTi alloy surface, about 34%. The coefficient of friction is 0.28 and the dominated wear mechanism of nanostructured tantalum nitride coating is abrasive wear with shearing mechanism.