Characterization of textured Cr2O3 layer formed on AISI440A stainless steel via anisotropic electropolishing for electrosurgical instruments

Abstract

This paper presents the development of a textured Cr2O3 layer on electropolished surgical AISI440A stainless steel with a layer thickness less than 50 μm for the miniaturization of electrosurgical instruments. The electropolished surgical AISI440A steel specimens were investigated using x-ray diffraction, scanning electron microscopy, atomic force microscopy, corrosion resistance testing, and contact angle measurements. The results showed that the textured Cr2O3 layer with a (202) preferred orientation possessed a texture coefficient greater than that for the (300) orientation, and in terms of lower surface roughness, a thicker Cr2O3 layer, which extends the passivation range, reduced the corrosion current density (Icorr) of 9.4 nA cm-2, and enhanced the corrosion resistance. The contact angle measurements revealed a large contact angle, indicating reduced surface energy and hydrophobic anti-adhesion property. This elucidated the relationship between the crystalline orientation and the properties of the textured Cr2O3 layer, which were attributed to anisotropic electropolishing.