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摘要:本实验采用了单因素研究方法，探讨了钝化液中加入硝酸镁对镀锌层蓝白钝化的腐蚀性能的影响，并通过硫酸铜点滴试验法和盐雾试验测定了钝化膜的耐腐蚀性能、通过擦拭法测定了钝化膜的结合力。实验结果显示：当铬酐浓度为0.1g/L，硫酸铵5g/L，醋酸0.6mL/L，硝酸镁6g/L，pH=1.90，电流密度1.5A/dm2，钝化温度为25℃，钝化时间为30s时得到的钝化膜光泽度较好，膜层的孔隙率不高，平整性很好，且具有良好的防腐蚀性能。这种配方下的钝化膜可耐硫酸铜点滴27s，用橡皮擦拭5次钝化膜剥离镀锌层，经过48h的盐雾试验，产生白锈的面积小于总面积的5%，膜层孔隙率平均约为20%。该配方所得到的数据充分地表明了硝酸镁中阴阳离子能很好地提高镀锌层蓝白钝化膜的防腐蚀性能，延长了耐腐蚀时间。本次实验研究的新工艺配方符合普通五金电镀对镀锌层蓝白钝化的的要求，可使用于五金电镀的大规模生产。21521
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毕业论文关键词：镀锌；蓝白钝化；硝酸镁
A study of blue and white passivation
Technology on galvanized zinc layer
Abstract: This experiment adopts single factor research method, discussing the effect of magnesium nitrate in passivity solution on the corrosion performance of blue and white passivity on galvanized layer. And through copper sulfate spot test and salt spray test the corrosion resistance performance of passivity film are measured. The adhesion strength of the passivity film and the porosity of the passivity layer are separately determined by wiping method and the sticker method. The results show that when the concentration of chromic anhydride is 0.1 g/L, ammonium sulfate 5 g/L, acetic acid 0.6 mL/L, magnesium nitrate 6 g/L, pH = 1.90, the current density of 1.5 A/dm2, passivity temperature 25℃, passivity time for 30s we can get better passivity membrane glossiness、low membrane layer porosity、good smoothness and excellent anti-corrosion performance. Under this formula, passivity film can be resistant to copper sulfate dripping test for 27s, 5 times before passivity layer stripping from galvanized layer. The white rust region is less than 5% after enduring salt spray test for 48h and the total layer porosity is about 20% on average. The data fully demonstrates that the anionic and cationic in magnesium nitrate can well improve the anti-corrosion performance of blue and white passivity membrane on galvanized layer, by prolonging the anti-corrosion time. The experimental study of new technology formula conforms to the common metal plating requirement for blue and white passivity on galvanized layer so that it can be used in metal plating for mass production.
Key words: zinc plating; blue and white passivity; magnesium nitrate
目 录
1引言 1
1.1镀锌蓝白钝化研究的概况及意义 1
1.2镀锌蓝白钝化的研究内容及目的 1
1.3镀锌蓝白钝化工艺在国内外研究的情况及发展趋势 2
1.4本课题要解决的问题 4
2镀锌钝化的技术原理 5
3工艺研究方法 8
3.1工艺研究方法 8
3.2钝化膜性能测定试验方法 8
4实验研究 11
4.1实验仪器、试剂、材料 11
4.1.1主要实验仪器 11
4.1.2主要药品、材料 11
4.2膜层的制备 12
4.2.1钝化液的配制 12
4.2.2钝化用试片的电镀 12
5试验结果及讨论 13
5.1实验结果 13
5.2工艺成份的作用与影响 13
5.2.1 铬酐 13
5.2.2 硫酸铵 13
5.2.3 醋酸 14