A new design for coating thin film alumina on stainless steel for biomedical applications

Biocompatibility is one of the essential characteristics of implants used in biomedical and dental applications. The biocompatibility may be affected by many factors, one of which and the most important one, is its corrosion resistance in highly aggressive body fluid. Corrosion of implants causes products of corrosion to accumulate in adjacent tissues and stimulate allergy in patients. Surface modification of stainless steel can minimize its corrosion significantly. Thin, dense film of alumina (Al₂O₃) coatings can provide an excellent biocompatibility as well as wear resistance. A new nozzle was modeled, designed, tested, and used to produce alumina coatings. Unlike the conventional plasma spraying, the new nozzle is designed based on the high velocity oxygen fuel (HVOF) process. The major accomplishment of this work is making the HVOF a feasible process for coating alumina with a high quality and low porosity suitable for biomedical applications.