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 double- layered tantalum/ tantalum nitride 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-indentation and nano-scratch methods in different loads. The results indicate that applying the uniform, homogeneous and crack free double- layered tantalum/ tantalum nitride with a thickness of about 1310 nm. Double- layered tantalum / tantalum nitride coating presented 7.9 GHz of hardness at a load of 700 μN and 6.5 GHz of hardness at a load of 1000 μN.
