Nanocomposite Ti-Si-N Coatings Deposited by Reactive dc Magnetron Sputtering for Biomedical Applications

Nanocomposite TiSiN coatings were prepared by reactive dc magnetron sputtering in a mixture of Ar and N-2 gases onto bio implantable 316L stainless steel substrates. X-ray diffraction analysis revealed that the TiSiN nanocomposite coatings are mainly composed of amorphous Si3N4 and TiN crystals. The presence of different phases like TiN, TiO2, and Si3N4 was confirmed from X-ray photoelectron spectroscopy analysis. Raman spectra of the as-deposited composite coatings exhibited characteristic peaks at 207.5, 305.8, 442.5, and 571.8 cm(-1). HRTEM indicated columnar microstructure. A higher hardness value of 35 GPa for the nanocomposite coatings was observed. The potentiodynamic polarization and electrochemical impedance spectroscopy measurements showed that the TiSiN nanocomposite coatings exhibited superior corrosion resistance compared with the Si3N4, TiN single layer, and the bare substrate in simulated body fluid solution.