Excimer laser treatment of NiTi shape memory alloy biomaterials

NiTi Shape Memory Alloys (SMA) are potential biomaterial candidates. However, due to its possible corrosion in physiological solution, dissolution of toxic Ni might be happening, rendering this material nonbiocompatible. We have used excimer laser surface treatment to improve corrosion resistance of NiTi SMA plates. Potentiodynamic tests in physiological Hank's solution show that the laser treatment performed in air improved all corrosion parameters. The surface is homogenized and a Scanning Electron Microscopy (SEM) observation indicates a decrease of corrosion pit size and numbers. Laser treatment improvement resistance is explained by a combination of the homogenization of the surface by melting, the hardening due to N incorporation and the thickening of the oxide layer.