Biological Corrosion Resistance and Osteoblast Response of 316LVM Polished Using Electrolytic Plasma

Abstract

As electrolytic plasma polishing (EPP) offers the advantages of strong shape adaptability, high efficiency, and environmental friendliness, it has great application prospects in biomedical material processing. However, the effect of EPP on the biological performance of the treated surfaces remains unclear. In the present study, the effects of EPP on the surface roughness, micro-morphology, corrosion behavior, and cell response of 316LVM were investigated. The results revealed that the surface roughness (Ra) was reduced from 0.3108 to 0.0454 µm upon EPP, and the sharp peaks and protrusions produced as a result of mechanical grinding were removed. The corrosion current density decreased from 1.129 to 0.164 µA/cm2, while the charge transfer resistance increased from 513.3 to 17,430 kΩ·cm2, which implied that EPP treatment could significantly improve the corrosion resistance of 316LVM. Furthermore, affected by the sharp ridges on both sides of the groove, the outward spreading of osteoblasts (MC3T3-E1) on the untreated samples was inhibited, and the edges were curled. The cells grew along the direction of the mechanical processing texture on the untreated samples, while they grew randomly in all directions on the surface treated using EPP, which adversely affected the growth, spreading, and migration of the cells.

Electrolyte component preference and surface integrity impact analysis for electrolytic plasma polishing of cobalt-chromium-molybdenum alloys

“…Electrolyte as one of the key factors, generally according to the different metals and alloys to choose the appropriate neutral salt solution. For instance, ammonium sulfate solution is suitable for various types of steel and its alloys [14][15], ammonium chloride and copper sulfate solution are commonly used for copper alloys [16], ammonium chloride and potassium chloride solution are utilized for aluminum and aluminum alloys [17][18], while ammonium chloride and potassium uoride solution are employed for titanium alloys [19][20]. When polishing cobalt-chromium alloys, sulfate solutions are generally used as the electrolyte, speci cally one or a mixture of ammonium sulfate solution, potassium sulfate solution and ammonium bisulfate solution.…”