The anti-corrosion property plays ail important role in determining the biocompatibility of metal implants. In this study, functionally graded diamond-like carbon coatings were deposited oil the Nitinol substrate by hybrid magnetron sputtering and plasma enhanced chemical vapor deposition. A scratch test was adapted to study the adhesion strength of the coatings. The Si/SiC graded layer (up to 150 rim thick) provided good adhesion between the coating and the substrate, Up to approximately 47.17 +/- 2.1 N. The effectiveness of corrosion protection for the coated specimen was investigated in Tyrode's simulated body fluid. It was found that adhesion strength had a great influence on the effectiveness of corrosion protection, and the better adhesion strength, the better Corrosion resistance. Compared to the others, the coating with a 150 nm thick Si/SiC graded layer provided better corrosion protection, and there existed no large amount of debonding and cracking of the coating around corrosion pits after the potentiodynamic polarization tests. (c) 2005 Elsevier B.V. All rights reserved.