| 摘要 |
PURPOSE:To dissolve and remove easily colored coating formed on the surface of a Mn-plated steel material so as to obtain a surface having metallic luster, by immersing the Mn-plated steel material in an aq. soln. of NH3 or NH4 salt. CONSTITUTION:An Mn-plated steel material is immersed in an aq. soln. contg. NH3 or NH4 salt (e.g., CH3COONH4) in concn. from 0.1% to saturation, or the soln. is spread on the steel material. As the result, the colored coating formed on the Mn-plated steel material is removed, in addn., no colored-coating is regenerated after water-washing and drying, consequently a surface excellent in chemical treatment property is obtained. Further addn. of 0.01-30% hydrogen peroxide soln. causes to retard the deterioration of the treating soln. Weakly acidic, or neutral soln., 5-7 in pH, also removes colored coating easily. |
