Surface modification and its mechanisms by in-process grinding technique

生物植入物，如人工关节和人工牙根，由于其形状非常复杂，要求高效率和精密加工。此外，生物植入物的小型化一直在发展，因此需要超精密加工技术。本研究的目的是阐明ELID（电解过程修整）磨削作为生物材料表面改性加工工艺的适用性。结果总结如下。(i)ELID磨削可以获得高质量的低表面粗糙度的表面。(ii)比较ELID磨削完成的表面和抛光完成的表面表明省略机加工后的额外的表面改性过程的可能性（iii）通过ELID磨削完成的表面具有生物相容性和特别高的耐腐蚀性相比，抛光表面，因为形成了厚的和稳定的表面改性的氧化物层。该表面不诱导细胞毒性反应，也不改变细胞的生理或功能行为。(iv)ELID磨削产生非常薄的硬化层，并在表面上产生压缩残余应力。这些改善了成品表面的机械性能。

Bio-implants, such as artificial joints and artificial tooth root, require high efficacy and precision processing, because their shapes are very complicated. In addition, the downsizing of bio-implants has been progressing, thus requiring ultra-precision processing techniques. The aim of the present study was to clarify the applicability of the ELID (Electrolytic In-process Dressing) grinding as a surface modification machining process for biomaterials. Results are summarized as follows. (i) ELID grinding can obtain a high quality surface with low surface roughness. (ii) Comparing the surfaces finished by ELID grinding and those finished by polishing indicates the possibility of omitting the additional surface modifying processes after machining (iii) A surface finished by ELID grinding has biocompatibility and a particularly high corrosion resistance compared to that of the polished surface because of the formation of a thick and stable surface-modified oxide layer. This surface does not induce a cytotoxic reaction nor alter the physiological or functional behavior of cells. (iv) ELID grinding creates a very thin, hardened layer and produces a compressive residual stress on the surface. These improve the mechanical properties of the finished surface.