Nanostructured Hydroxyapatite Granules for Plasma Spray Coating on Titanium Alloy

摘要

In medical implants, the use of hydroxyapatite (HA) coating as the intermediate layer between metal implants with human tissues is not a strange occurrence as it has been in practice for several decades. However, the life span and stability of this plasma-sprayed coating has always been questionable, due to two major shortcomings. The first is the transformation of a large portion of the HA from crystalline to amorphous form due to the high-operating temperature of the plasma spraying proces. This leads to the dissolution of the material inside the patient's body and can become toxic for the patient. The second is the reduced mechanical properties such as tensile strength between the HA layer and the implant as a point of potential failure in prosthesis. Bioceramic composite coatings are alternatives but they possess poor adhesion strength, which lead to problems such as debris accumulation and implant loosening.