Review of Plastic Plating-英语电镀介绍RD.ppt

电位差 Potential difference 微孔 Micro pores 厚度 Thickness 晶格结构 Lattice Structure 2012/11/22 * 三层镍抗腐蚀因素 Anti corrosion feature of triple-layer nickel 2012/11/22 * 三层镍电位差 Step-potential of Triple-layer Nickel Coating 合适的电位差可以引导腐蚀发生在光镍层。当腐蚀发生时，在封口镍与光镍，光镍与半光镍之间电位差形成了原电池，由于光镍的电位最负，在腐蚀电池中呈阳极被腐蚀，从而是使指向基体的穿透腐蚀变为集中在光镍层的横行腐蚀得以延缓 Appropriate potential step can lead corrosion occurred in bright nickel layer. When corrosion occurs, potential difference betweeen sealing nickel and bright nickel, between bright nickel and semi-bright nickel form the primary batteries. As the bright nickel has the most negative potential, it makes corrosion mostly spread in the layer of bright nickel. So that, the corrosion penetration buffers in this layer. 2012/11/22 * 电位差腐蚀机理 The Corrosion Mechanism of Potential Differences 微孔足量且均匀的分布可起到分数腐蚀的作用，减小单个腐蚀的面积和深度，减少可见腐蚀点数量。 Adequate and uniform of microporous distribution has a measurable effect of anti corrosion by reducing the area and depth of single corrosion point, and the number of visible corrosion points. 一般微孔密度在5000-10000个/cm2时耐蚀性开始提高，在10000-40000个/cm2时耐蚀性显著提高，在80000个/cm2以上镀层光泽下降明显，影响外观。 Generally, when micropore density is between the 5000-10000/cm2, the corrosion resistance starts to improve; between 10000-40000/cm2, the corrosion resistance improves significantly. When it’s above 80000 /cm2, the coating will become glossy. 2012/11/22 * 微孔数 Number of Micropores 内饰件一般要求 : CASS≤24h 总镍厚度5-10 μm General requirements of interior trims: CASS ≤ 24h Total nickel deposits thickness: 5-10 μm 外饰件一般要求 CASS24h 总镍厚度10-25 μm General requirements of exterior trims : CASS 24h Total nickel deposits thickness: 10-25 μm 2012/11/22 * 厚度 Thickness 双层镍优良的耐蚀性能还得益于镀层本身的晶体结构，从下面的金相图片可见，半光镍层金属为柱状晶体，而光镍层金属为层状晶体，两者互成垂直，对外界腐蚀性物质起到一定的阻挡作用。 Good corrosion resistant performance of double-layer nickel is also benefited from its crystal structure. As shown in the metallographic picture below, the crystal structure of semi-bright