SURFACE COATING LAYER BY IRON AND STEEL AND SURFACE TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a surface treatment method for a surface coating layer by the iron and steel having a flat surface at an atomic level. SOLUTION: The surface coating layer having an electrochemically surface treated surface of <=10 nm in center line surface roughness Ra and <=30 nm in maximum height and having excellent flatness by the iron and steel having the excellent flat surface is subjected to surface cleaning to remove the dirt and oxidized film covering the surface by an electrochemical technique and is then immediately immobilized and the treatment conditions of a high passivation potential, a treating solution of a high temperature, long passivation holding time, and repetition of passivation and cathode reduction are combined, by which the surface is gradually reconstituted by the crystalline oxidized film and a step-terrace structure is formed. The surface flat at the atomic level in the terrace grown or expanded at this time is obtained.