Fabrication and Tribo-Corrosion of Titanium-Based Composite Coatings

Abstract

When hip joints of human are severely damaged, due to osteoarthritis for instance, and thus have lost their ability of self-regenerating, artificial implants are often in need. The implants have to be with high biocompatibility so that no rejection from the natural tissues and the immune system will occur. For this reason titanium and its alloys are widely used as the artificial orthopedic implants in recent years. The titanium-based implants will degrade, not only due to corrosion in human body fluid, but also wearing and fretting caused by mechanical stress between prosthesis and surrounding bone tissues. In present study, composite layers are supposed to fabricate on the surface of titanium alloy (Ti6Al4V) using a high power diode laser. Some ceramic phases are expected to be introduced as reinforcement for enhancing the properties of the base material including hardness, corrosion and wearing resistances. Microstructure, compositions and phases of the laser-fabricated layers will be investigated by scanning electron microscope (SEM), energy dispersive X- ray spectroscopy (EDX) and X-ray power diffraction (XRD) respectively. Hardness of the laser-fabricated layers will be tested by a digital Vickers micro-hardness tester. Corrosion resistance will be studied based on open circuit potential (OCP) and potentiodynamic polarization test using a potentialsat. The surface morphology of fabricated layer after fretting wear will be compared with base material using atomic force microscope (AFM) as well. Throughout the materials characterization techniques, the corrosion and fretting wear behavior will be explained in terms of the change in the surface properties of the laser-fabricated layers.