Owing to its good biocompatibility and low cost, stainless steel is one of the most widely utilized biomaterial. However, longtime assessment of stainless steel has shown problems related to material degradation, especially localized corrosion and bio-film formation. In addition, the leaching of toxic nickel and chromium ions from stainless steel leads to additional health complications. Here, we utilized submerged friction stir processing, a severe surface deformation technique for significantly enhancing its durability, bio-activity as well as antibacterial resistance. The processing was done with a wide variation in strain rates to produce tunable surface microstructure. High strain-rate processing resulted in nearly single-phase fine-grained microstructure, while slow strain-rate processing developed a dual-phase fine-grained microstructure. The bio-corrosion rate of processed steel was reduced by more than 60 % along with significant enhancement in the pitting resistance. The processed steel showed nearly no bacterial adhesion/biofilm formation, evaluated using S. aureus and E. coli bacterial strains. Further, the processed stainless steel surface demonstrated minimum leaching of the toxic elements, significantly enhancing its appeal for bio-implant applications. The observed behavior was explained based on the formation of a stable passive layer, rich in Cr₂O₃, as determined using x-ray photoelectron microscopy (XPS) and increased hydrophilicity.

由于其良好的生物相容性和低成本，不锈钢是使用最广泛的生物材料之一。但是，对不锈钢的长期评估显示出与材料降解有关的问题，尤其是局部腐蚀和生物膜形成。另外，从不锈钢中浸出有毒的镍和铬离子会导致其他健康问题。在这里，我们采用了浸没式摩擦搅拌工艺，一种严格的表面变形技术，可以显着提高其耐用性，生物活性以及抗菌性。加工过程中应变率变化很大，以产生可调节的表面微观结构。高应变速率处理导致近乎单相的细晶粒组织，而慢应变速率处理则形成了双相的细晶粒组织。加工后的钢的生物腐蚀率降低了60％以上，同时耐点蚀性显着提高。经处理的钢经评估显示几乎没有细菌粘附/生物膜形成金黄色葡萄球菌和大肠杆菌菌株。此外，加工后的不锈钢表面显示出最少的有毒元素浸出，大大增强了其在生物植入物应用中的吸引力。使用X射线光电子显微镜（XPS）确定了稳定的，富含Cr ₂ O _3的钝化层的形成，从而解释了观察到的行为，并通过增加的亲水性进行了解释。