Surface characterization of Fe–10Al–25Mn alloy for biomaterial applications

Abstract

The austenitic stainless-steel biomaterial, AISI 316L stainless steel, is one of the most widely used for orthopedic or prosthetic implant devices because it is easy to manufacture at a relatively low cost. However, corrosion is a challenging issue related to major alloying compounds with body fluids and wear. Therefore, this study aimed to develop a biomaterial of Fe–Al–Mn alloys by minimizing chromium (Cr) and nickel (Ni) contents. In the research, an attempt has been made to increase the corrosion resistance of Fe–10Al–25Mn alloy using plasma nitriding, which was considered one of the most cost-effective surface treatments. The processes were carried out at various treatment temperatures between 350 and 550 °C, with a pressure of 1.8 mbar in 3 h. Several tests were performed, such as chemical compositions, scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS), hardness, and corrosion. The results indicated that the treatment of plasma nitriding at temperatures up to 500 °C significantly enhances the corrosion resistance and increases the hardness of the alloy. At 500 °C, the percentage of nitrogen atoms reaches a peak and then decreases. It means that the nitride formation process on the alloy surface occurs more massively. The amount of nitrogen deposited on the surface of the Fe–10Al–25Mn alloy, as well as a thin layer of iron nitride, is noticeable in the SEM-EDS test. Furthermore, the formation of phases due to the nitriding temperature significantly impacts the alloy properties.