Structural, mechanical and optical properties of nitrogen-implanted titanium at different pulse frequency

¹ Physics Department, Faculty of Science, Sohag University, 82524 Sohag, Egypt
² Physics Department, College of Science, Qassim University, P.O. 6644, 51452 Buryadh, Kingdom of Saudi Arabia
³ Forschungszentrum Dresden-Rossendorf, Institut für Ionenstrahlphysik und Materialforschung, 01328 Dresden, Germany

^a e-mail: mraaif@daad-alumni.de

Received: 29 September 2012
Revised: 8 January 2013
Accepted: 31 January 2013
Published online: 2 April 2013

Abstract

Plasma-immersion ion implantation (PIII) is a potent method to obtain hard and wear-resistant surface on Ti by nitrogen implantation. This presentation is one part of a sequence of experiments to optimize the microstructure and physical properties of TiN through adapting the plasma-processing parameters. In this work, nitrogen ions were implanted into samples of pure Ti at different nitrogen pulse frequency without using any external source of heating. The nitrogen-implanted surfaces were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES), optical microscope, nano-indentation technique, ball-on-disk type tribometer, surface profilemeter, Tafel polarization technique for corrosion performance and ellipsometry. The outcomes show that, nitrogen PIII is an effectual method for nitriding titanium and nitrogen pulse frequency affected the microstructure and physical properties of the treated Ti. X-ray diffraction depicted the formation of α-Ti (N) and the cubic TiN after implanting titanium by nitrogen and the thickness of the nitrided layer increased as the nitrogen pulse frequency increased. The wear and corrosion resistance of the nitrogen-implanted titanium are improved and the friction coefficient decreased from nearly 0.8 for the un-implanted titanium to 0.3 for the implanted titanium, this ascribed to the formation of the titanium nitrided phases. Ellipsometric measurements were carried out on the PIII titanium samples at different nitrogen pulse frequency. The ellipsometric measurements show that, the thickness of the nitrided layer and surface roughness increased while the refractive index decreased with increasing nitrogen pulse frequency.