316L Stainless Steel/Hydroxyapatite Composite Materials for Biomedical Applications

Hydroxyapatite (HAp) is known as one of the most important biomaterials used for orthopedic and dental applications due to chemical composition similar to that of bone and bioactive properties. However, due to its reduced resistance, HAp should be mixed with different components in order to create composite materials. A good example is austenitic stainless steel (AA 316L), as a class of metallic materials used for biomedical applications. The aim of this chapter is to show a series of our group studies for obtaining a hybrid metal-ceramic composite by powder metallurgy, the physicochemical, mechanical, and biological properties of these hybrid composites and the investigation of possible functional coating layers and adherent bioactive hydroxyapatite Ca10(PO4)6(OH)2 on the metal of 316L stainless steel, correlating our data with literature data. Hardness properties of the obtained composites are close to those of human bones. In biological systems, could be observed that after 6 months, the relevant metals (Fe, Mn, Cr, and Ni) concentration (ppb), that may be released from composite materials in simulated physiological fluids (SBF), is practically zero