板材平整度对锆化膜耐蚀性能的影响研究

Study on the Effect of Sheet Flatness on the Corrosion Resistance of Zirconium Film

为了从机理上明确锆化膜的耐蚀性与基材表面平整度的关系,通过化学抛光分别改变冷轧板、铝合金板表面平整度,与未处理的冷轧板、铝板进行对比,在试样表面制备锆化膜,利用扫描电镜(SEM)分别观测锆化膜的微观形貌;利用电化学方法、盐雾试验箱、循环交变试验机、漆膜附着力检测设备等仪器测试钝化膜的耐蚀性能、漆膜附着力。结果表明:抛光后的冷轧板、铝合金板外观光滑平整,制备的锆化膜颗粒排布均匀致密,粗糙度明显降低,锆化膜的腐蚀电流较小,阻抗半径较大;未抛光的冷轧板、铝合金板外观粗糙不平整,制备的锆化膜颗粒大小不一,排布无规律;冷轧板、铝合金板锆化膜经冲击、杯突和划格实验的附着力检测后结果合格;经1000 h盐雾测试后,抛光后平整表面的冷轧板漆膜单边最大扩蚀宽度约1.9 mm,漆面无气泡;未抛光冷轧板漆膜单边最大扩蚀宽度约2.3 mm,漆面无气泡;抛光铝合金板经过30个循环交变检测后,漆膜单边扩蚀宽度2.0 mm,漆面无气泡;未抛光铝合金板经过30个循环交变检测后,漆膜单边扩蚀宽度2.6 mm,漆面无气泡。

In order to clarify the relationship between the corrosion resistance of zirconium films and the surface flatness of sheets from amecha-nism perspective,chemical polishing was used to alter the surface flatness of cold-rolled steel sheets and aluminum alloy sheets.These modified surfaces were compared with untreated cold-rolled and aluminum sheets.Zirconium films were prepared on the sample surfaces,and their micro morphology were observed using scanning electron microscopy(SEM).Electrochemical methods were employed to test the corrosion resistance of the passivation films.The corrosion resistance of the films and the adhesion of paint film was evaluated using salt spray test chamber,cyclic alternation tester and paint adhesion testing equipment.Results showed that the polished cold-rolled steel sheets and aluminum alloy sheets ex-hibited smooth and even appearances.The zirconium films prepared on these polished surfaces displayed a uniform and dense particle distribu-tion,with significantly reduced roughness.The corrosion current of the zirconium films was lower,and the impedance radius was larger.In con-trast,the unpolished cold-rolled and aluminum alloy sheets appeared rough and uneven,and the zirconium films prepared on these surfaces had irregular particle sizes and arrangements.After impact,cup tests and cross-cut adhesion tests,the adhesion of the zirconium films on both cold-rolled and aluminum alloy sheets met the requirements.After 1000 h of salt spray testing,the maximum single-sided expansion width of the cold-rolled plate paint film on the polished flat surface was approximately 1.9 mm,with no bubbling on the paint surface.For the unpol-ished cold-rolled sheets,the maximum single-sided expansion width of paint film was about 2.3 mm,also with no bubbling.For the polished aluminum alloy sheets,the paint film exhibited a single-sided expansion width of corrosion of 2.0 mm after 30 cycles of alternating testing,with no bubbling on the paint surface.Conversely,the unpolished aluminum alloy sheets showed a single-sided expansion width of corrosion of 2.6 mm after the same number of cycles,with no bubbling.