Surface modification of titanium by nitrogen ion implantation

Nitrogen ions were implanted in high purity titanium at various doses. The nitride phase, TiN, was identified using either grazing incidence X-ray analysis or transmission electron microscopy. AES depth profile of nitrogen was altered from Gaussian-like to a rectangle with increasing nitrogen doses. Both dissolved nitrogen and tendency to form TIN increased precipitates with increasing nitrogen doses. These TIN precipitates that size were several tens of nm were observed at a lower dose. They grew larger as nitrogen dose increased. The dynamic ultra-microhardness rose to a thickness of within 200 nm of the surface owing to TiN formation, resulting in improved wear resistance of titanium. The wear volume was minimum at a dose of 5 x 10(21) N-2(+) m(-2). (C) 1999 Elsevier Science S.A. All rights reserved.