Coating of the Surface of 316L Stainless Steel with Hydroxyapatite Produced from Eggshell Using the Sol-Gel Method

In this study, the production of high-yield and purity calcium nitrate from eggshell, a biological waste, and the usability of the obtained calcium nitrate in the production of hydroxyapatite (HAP) by the sol-gel method were investigated. In addition, the obtained HAP was used to coat 316L steel using the dip coating method. For this purpose, calcium nitrate, which will be used as a precursor in HAP production, was produced from chicken eggshells with high calcium carbonate content. The surface of 316L stainless steel discs was coated with sol-gel obtained from a mixture of calcium nitrate and triethyl phosphite by dip-coating method. Then, the 316L discs were dried and heat treated at 500 °C to form HAP on their surfaces. XRD and SEM techniques were used for the characterization of the obtained HAP structure. Unlike previous studies, it has been shown that chicken eggshell, a biological waste, can be used to produce HAP, a biocompatible material, and the surface of 316L stainless steel can be coated with the produced HAP.