脉冲电镀镍磷合金

摘要

随着人们对汽车耐蚀性要求的提高，纯锌镀层已不能满足要求，经研究发现，锌钴合金镀层由于有钴的加入，耐蚀性大大提高，镀层耐蚀性好，外观光亮，不易褪色，易于钝化，其应用越来越广。

本论文研究了脉冲电镀锌钴合金的最佳工艺条件，探讨了电流密度、频率、通断比、工作时间、光亮剂用量和主盐比例等六个因素对镀层性能的影响。通过对其光亮度、耐蚀性、附着力的测试，以及通过XRD、SE(M)和tafel曲线的检测，对镀层的成分及表面现象进行了分析，最终筛选出最佳的工艺条件。结果表明：电流密度大于2.0 A/dm2时，得到的镀层平整且均匀，附着力好，小于2.0 A/dm2时，沉积速度减慢，镀层不均匀，颗粒较大且附着性差；施镀时间越长，锌镀层越厚。综上所述该工艺的最佳工艺条件是：电流密度为2.0 A/dm2，频率为1000Hz，通断比为5:5，时间为10min，光亮剂用量为为30ml/L，主盐比例为CoSO4

0.02M，ZnSO4 0.4M。

关键词：脉冲电镀,锌钴合金,镀层性能,影响因素

Abstract

As people for car corrosion resistance requirements of the improved, pure zinc plating already cannot satisfy requirements, the study found that, zinc-cobalt alloy coatings with cobalt to join, corrosion resistance greatly improved, coating corrosion resistance, good appearance light, not easy to fade away, easy to passivation, its used more and more widely.

This paper studies the pulse electric galvanizing the optimum process conditions of cobalt alloys, discusses the current density, frequency, hige ratio, working hours, brightener dosage and lord salt proportion of six factors on the influence of coating performance. Through its brightness, corrosion resistance and adhesion tests, and through the XRD, SE (M) and Tafel curve of the testing, analyzes the composition of the surface coating and phenomenon, eventually selected the best technological conditions. Results show that: Current density is greater than 2.0 A/dm2, get on the flat and uniform, good adhesion, less than 2.0 A/dm2, sedimentary speed slow down, not even,coating grain larger and adhesion poor; With the more time the plating,zinc plating is thicker. To sum up the process the optimum technological conditions are: Current density is 2.0 A/dm2, Frequency is 1000Hz, Hige than 50, Time is 10min, potency of Brightener is 30ml / L, The ratio of the main salt 0.02M CoSO4, 0.4M ZnSO4.

Keywords: Pulse electroplating, zinc-cobalt alloy, coating performance, influencing factors

目录

引言 (1)

1文献综述 (2)

1.1介绍脉冲电镀 (2)

1.2脉冲合金电镀 (3)

1.2.1 电镀合金 (3)

1.2.2 脉冲锌基合金 (5)

1.3锌钴合金的发展及研究现状 (6)

1.4锌钴合金镀液体系及其镀层的特点 (8)

1.5碱性电镀锌钴合金 (9)

1.5.1 碱性电镀的介绍 (9)

1.5.2 镀液中成分的作用 (10)

1.5.3 影响镀层组成的主要因素 (10)

1.5.4 镀液的维护 (11)

1.6碳钢电镀前处理工艺及其对镀层的要求 (12)

1.7本实验研究内容 (13)

2 实验部分 (14)

2.1实验的原理 (14)

2.1.1 阴极反应 (14)

2.1.2 阳极反应 (14)

2.2实验方案 (14)

2.3主要试剂与仪器 (15)

2.4实验步骤 (16)

3. 结果与讨论 (19)

3.1XRD测试 (19)

3.2锌钴合金工艺条件的研究 (19)

3.2.1 电流密度对镀层性能的影响 (19)

3.2.2 频率对镀层性能的影响 (21)

3.2.3 通断比对镀层性能的影响 (22)

3.2.4 电镀时间对镀层性能的影响 (23)

3.2.5 光亮剂用量对镀层性能的影响 (24)

3.2.6 主盐比例对镀层性能的影响 (25)

3.3脉冲电镀锌钴的电化学测试 (27)

3.4脉冲电镀锌钴的电镜和能谱测试 (28)

3.4.1电镜分析 (28)

3.4.2.能谱分析 (29)

4 结论 (34)

参考文献 (35)

谢辞 (37)