Effect of carbon ion implantation on the structure and corrosion resistance of OT-4-0 titanium alloy

This work presents the results of investigation of the properties of OT-4-0 titanium alloy surface layers subjected to carbon implantation. Polished samples were implanted with carbon doses:of 5 x 10(15), 1 x 10(16), 1 x 10(17), and 2 x 10(17) C+ cm(-2) at an energy of 100 keV. The corrosion resistance was examined by the Stern and potentiodynamic methods in 0.9% NaCl solution at a temperature of 37 degrees C. The composition and structure of the implanted layers were investigated by XPS, SIMS and TEM. The carbon implantation produced TiC precipitates at doses of 1 x 10(16) C+ cm(-2) or less; and a continuous solid layer of TiC at the further doses. The results from the electrochemical measurements provide evidence that carbon implantation at higher doses increases the corrosion resistance. The hardness of OT-4-0 titanium alloy is also improved. (C) 1999 Elsevier Science S.A. All rights reserved.