| DUAN Hai-dong,SUN Huan-wu,JI Gang-qiang,ZHANG Dong-guang,SUN Jin-yan,YANG Dong-liang.Surface Morphology and Electrochemical Characteristics of 316LVM Polished by Electrolytic Plasma[J],50(8):396-403 |
| Surface Morphology and Electrochemical Characteristics of 316LVM Polished by Electrolytic Plasma |
| Received:September 14, 2020 Revised:November 24, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2021.08.040 |
| KeyWord:316LVM electrolytic plasma polishing surface morphology phosphate buffer solution grain size corrosion resistance |
| Author | Institution |
| DUAN Hai-dong |
College of Mechanical and Vehicle Engineering,, Taiyuan , China |
| SUN Huan-wu |
College of Mechanical and Vehicle Engineering,, Taiyuan , China ;National Demonstration Center for Experimental Coal Resource and Mining Equipment Education, Taiyuan University of Technology, Taiyuan , China |
| JI Gang-qiang |
College of Mechanical and Vehicle Engineering,, Taiyuan , China |
| ZHANG Dong-guang |
College of Mechanical and Vehicle Engineering,, Taiyuan , China |
| SUN Jin-yan |
College of Mechanical and Vehicle Engineering,, Taiyuan , China |
| YANG Dong-liang |
College of Mechanical and Vehicle Engineering,, Taiyuan , China |
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| Abstract: |
| The aims of this study is to obtain the influence of electrolytic plasma polishing on the surface morphology of 316LVM implant stainless steel and its electrochemical characteristics in phosphate buffer solution and solve the surface polishing problem of complex shaped implants. After wire cutting and surface preprocessing, the raw materials were made into 20 mm×15 mm×3 mm test samples. The samples were polished by mechanical polishing and electrolytic plasma polishing respectively. Mechanical polishing was carried out on an abrasive belt polishing machine by using 600 mesh, 800 mesh, 1200 mesh, 2000 mesh, and 5000 mesh abrasive belts and polished step by step. In the electrolytic plasma polishing, the voltage was 300 V, the electrolyte was 3wt.% (NH4)2SO4 aqueous solution, the temperature was 85~90 ℃, and the polishing time was 15 min. The surface roughness and micro morphology of the samples were tested by roughness meter and scanning electron microscope, the element composition and phase of samples were tested by energy dispersive spectrometer and X-ray diffractometer, and the electrochemical test in phosphate buffer solution was carried out by electrochemical workstation. The results showed that electrolytic plasma polishing reduced the surface roughness of the sample from 0.5 μm to 0.089 μm, the mechanical processing traces of the sample was removed, and the sample was smooth and bright. After mechanical polished, the chemical elements of the sample did not changed significantly, and the contents of Fe and Cr of the sample polished by electrolytic plasma polishing increased. The position and intensity of the X-ray diffraction peaks of mechanical polished samples did not changed significantly. After electrolytic plasma polishing, the intensity of the diffraction peak at the diffraction angle of 43.5° was significantly reduced and at the diffraction angle of 74.5° was significantly increased. At the same time, the FWHM of each peak was significantly reduced. The self-corrosion potential of mechanically polished and electrolytic plasma polished samples in phosphate buffer solution increased from –0.252 V to –0.232 V and –0.214 V, and the corrosion current density decreased from 1.611 μA/cm2 to 0.5867 μA/cm2 and 0.1582 μA/cm2, the polarization resistance increased from 28.876 kΩ to 64.682 kΩ and 251.262 kΩ. It can be concluded that electrolytic plasma polishing can effectively reduce the surface roughness of 316LVM and improve the surface flatness. After electrolytic plasma polishing, the Fe and Cr element content increases, the grain size increases, and manifests the (220) crystal plane preferential orientation. Electrolytic plasma polishing can improve the corrosion resistance of 316LVM in PBS. |
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