Thin Solid Films, 141 (1986) 59-69 METALLURGICAL AND PROTECTIVE COATINGS 59 X-RAY PHOTOELECTRON SPECTROSCOPY STUDIES OF HARD COATINGS FORMED BY TITANIUM IMPLANTATION ON 304 STAINLESS STEEL M. R. NAIR, D. C. KOTHARI, A. A. RANGWALA AND K. B. LAL Department of Physics, Universityof Bombay, Vidyanagari, Bombay 400098 (India) P. D. PRABHAWALKAR AND P. M. RAOLE Regional Sophisticated Instrumentation Centre, Indian Institute of Technology, Powai, Bombay 400076 (India) (Received May 20, 1985; revised November 8, 1985; accepted January 9, 1986) Titanium ions are implanted (at 30 keV) in 304 stainless steel to a dose of 1.8 × 1017 ionscm -2 using 15 ~tAcm -2 and 5 ~tAcm -2 beam current densities for specimens 2 and 3 respectively. X-ray photoelectron spectroscopy (XPS) measure- ments are performed at different temperatures. The microhardness of implanted and unimplanted specimens is also measured. In specimen 2 the microhardness does not increase significantly and XPS measurements give evidence of carburized surface alloy formation. At 250 °C TiO 2 is detected on the surface and it migrates into the bulk phase above 350 °C. In specimen 3 the XPS measurements exhibit an absence of iron owing to the radiation-induced segregation of titanium on the surface. This specimen shows an increase in microhardness. The XPS measurements reveal a layer of (TiCzC) on the surface which is suggested to be responsible for the increase in microhardness. Upon heating, TiCx is seen to move into the bulk phase and the carbon concentration is increased. These changes occurring at higher temperatures are suggested as having an effect on the wear-resistant properties of titanium-implanted 304 stainless steel. 1. INTRODUCTION It is now well established that ion implantation can improve the tribological properties of metals 1-3. In many applications it is desirable to have a metal surface with both corrosion- and wear-resistant properties. 304 stainless steel (304 SS) is known to have a corrosion-resistant surface. For obtaining wear-resistant surfaces on steels titanium is seen as a good candidate 3'4. Titanium alloys are found to have superior mechanical properties. The present study is confined to understanding the changes in hardness taking place after titanium implantation on 304 SS. Hirvonen et al. 5 reported an improvement in the wear resistance of 304 SS by titanium implantation. Using Auger electron analysis, Singer 4'6 reported that the reason for the improvement could be the formation of a carburized amorphous alloy Fe-Ti-C on the surface of steel. Oliver et al. 7 observed no significant increase in the microhardness of titanium-implanted steel. Pethica et al. 8 observed that 0040-6090/86/$3.50 © Elsevier Sequoia/Printed in The Netherlands