| 316L stainless steel is widely used in biomaterial, especially in interventional cardiology, because of its good corrosion resistance and blood compatibility. Although 316L stainless steel has shown excellent performance in clinic, it always is an attractive object to further improve the corrosion resistance and blood compatibility of 316L stainless steel. In this paper, plasma immersion ion implantation (PBII) was used to improve the corrosion resistance and blood compatibility of 316L stainless steel. The influence of implanted ion and dose on the surface component, surface properties and blood compatibility was studied.The micro-pores, on the surface of 316L stainless steel, were fabricated by combining magnetron sputtering and anodizing. The surface morphology of Al film and micro-pores on the surface of 316L stainless steel was examined by SEM. The nitrogen, oxygen and fluorin PBII were performed on 316L steel with doses of 1×1017ions/cm2, 6×1017ions/cm2, respectively. The surface composition was analyzed by X-ray Photoelectron Spectroscopy. Electrochemical tests were performed to analyze the corrosion resistance in Tyrode's stimulated body fluid. The contact angle was measured to evaluate the wettability of 316L stainless steel surface, under different treatments. The tests of platelet adhesion, hemolysis and moving cruor time were carried out to investigate the blood compatibility of the initial and treated 316L stainless steel.The results show that, the surface composition was changed, under ion implantation, chemical state of implantation element changed with the increasing of implantation dose. For nitrogen ion implanted samples, when the dose was low, N ion presented as solid solution, Fe ion presented as simple substance; and when the dose was higher, N ion existed as CrN and solid solution, Fe ion existed as Fe2/3/4N; with the increasing of dose, the atomic percent of N raised. For oxygen ion implanted samples, when the dose was low, the presence of Fe in elemental, as Fe2+ in oxide form and with the increasing of dose, as Fe3+ in the form of oxyhydroxides of the surface of samples, Cr was present as Cr2O3. For fluorin ion implanted samples, the present of fluorin did not change with the increasing of dose; FeF2, FeF3 and CrF3 were found on the surface of implanted samples.The results of electrochemical tests showed that, the corrosion resistance enhanced, with the treatment of plasma immersion ion implantation. What's more, the corrosion resistance weakened, with the increasing of implantation dose. The results of wettability tests indicated that, contact angle increased with the treatment of ion implantation and surface pores. The results of blood compatibility tests suggested that plasma ion implantation could reduce hemolysis rate, increase cruor time and decrease the adhesion density of platelet, thus enhanced the blood compatibility of 316L stainless steel. The formation of surface pore could improve the cruor resistance of 316L stainless steel, thus enhanced the blood compatibility. That is to say, ion immersion could enhance the blood compatibility of 316L stainless steel with surface pores. |
PDF Full Text Request