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• 676 • 【工艺开发】 不锈钢槽体表面钝化工艺的优化 杨明悦，李雨，刘定富* （贵州大学，贵州 贵阳 550025） 摘要：以 50%(体积分数)的硝酸溶液对 304 和 316 化学镀镍用不锈钢槽体进行钝化处理，采用单因素试验和正交试验方法考察了 钼酸铵及氧化钇的添加量、钝化时间和钝化温度对 304 和 316 不锈钢槽体表面钝化膜孔隙率的影响，确定了优化的钝化工艺条件 如下：钼酸铵和氧化钇的添加量分别为硝酸质量的 4.0%和 0.4%，304和 316不锈钢的钝化温度分别为 40 °C和 35 °C，钝化时间 5 h。通过扫描电镜观察了钝化前后不锈钢的表面形貌，测定了钝化膜的组成。结果表明，钼酸铵和氧化钇的加入使钝化膜的孔隙 率显著降低，提高了钝化膜的耐蚀性。优化工艺制备的钝化膜主要由 Cr、Fe、Ni和Mo的氧化物组成，膜层平整致密。 关键词：不锈钢；钝化；硝酸；钼酸铵；氧化钇；耐蚀性 中图分类号：TG178 文献标志码：A 文章编号：1004 – 227X (2015) 12 – 0676 – 05 Optimization of passivation process for surface of stainless steel tank // YANG Ming-yue, LI Yu, LIU Ding-fu* Abstract: The 304- and 316-type stainless steel tanks for electroless nickel plating were passivated with 50vol.% nitric acid solution. The effect of the amounts of ammonium molybdate and yttrium oxide as well as passivation temperature and time on the porosity of passivation coatings on surfaces of 304- and 316-type stainless steels was studied by single factor experiment and orthogonal test. The optimized process conditions were determined as follows: amounts of ammonium molybdate and yttrium oxide are 4% and 0.4% (by mass of nitric acid) respectively; passivation temperature is 40 °C for 304-type stainless steel and 35 °C for 316-type stainless steel; and passivation time 5 h. The surface morphologies of the stainless steels before and after passivation were observed by scanning electron microscope and the compositions of the passivation coatings were analyzed. It was found that the porosity of passivation coating is remarkably decreased by the addition of ammonium molybdate and yttrium oxide, leading to an improvement of corrosion resistance of the passivation coatings. The passivation coatings prepared under the optimized conditions consist of the oxides of Cr, Fe, Ni, and Mo, and are level and compact. Keywords: stainless steel; passivation; nitric acid; ammonium molybdate; yttrium oxide; corrosion resistance First-author’s address: School of Chemistry and Chemical Engine