Crack Analysis on Ti-6Al-4V ELI Coated with Commercial Hydroxyapatite for Implant Material: Literature Review

Abstract

Ti-6Al-4V Extra Low Intertitial (ELI), a type of titanium alloy that is commonly used for implant material. However, use of Ti-6Al-4V ELI still has some problems. The main one is oxide layer on the surface can be detached during application due to corrosion process. Such corrosion debris is a toxic substance to the human body. It is, therefore, necessary to modify the surface of the implant to avoid corrosion process by using coating method. A good coating material for orthopedic implants comes from ceramics, namely hydroxyapatite (HA). However, there are also an obstacle, HA coating on titanium, sometimes not evenly across the surface, causing cracks on the coating layer surface. There are two methods that are often used in coating materials, namely Electrophoretic Deposition (EPD) and Dip Coating. This study analyzed number of literatures using a searching engine of international reputable journals Science Direct, Pubmed on biomaterials and biomedicine fields using the keywords of Ti-6Al-4V ELI, hydroxyapatite, cracks, EPD method and Dip Coating. This literature review may useful for the readers and researchers, in order to choose the best method for crack reduction in the coated implants. Dip Coating method is better than EPD method in point of view simplicity and cost. Moreover, the coating layer is evenly distributed, no build-up of HA in several surface areas, so that cracks on surface are minimized.