Analysis on Eight Common Defects and Root Causes in Electroplating of Precision Hardware Parts

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Electroplating is a surface treatment technology that deposits a thin layer of other metals or alloys on metal surfaces based on the electrolysis principle. Through electrolysis, a metallic film adheres to the surface of metals or other materials. This process effectively prevents metal oxidation and rust, and improves wear resistance, electrical conductivity, reflectivity and corrosion resistance. It also enhances the aesthetic appearance of products. As a matter of fact, electroplating is also applied to the outer surface of many coins.Nevertheless, various defects may occur during the electroplating process. The eight most common issues are listed as follows:

1. Plating BlisteringAlso known as bubbling. This defect is mainly caused by surface imperfections on the workpiece or gas expansion underneath the plating layer. Insufficient adhesion of the coating can also lead to blistering. It should be noted that blistering is different from substrate bulging.
2. Burnt Plating LayerThe coating appears rough and dull. In severe cases, the surface is sharp enough to scratch gloves. This problem is generally triggered by excessive local current density.
3. Dull Finish (Overall Discoloration)The whole or partial surface suffers from low gloss, presenting a dim, foggy or whitish appearance.
4. Exposed Base MaterialThe underlying coating or base substrate becomes visible, mostly seen as exposed copper or raw material.
5. Plating PeelingCaused by poor adhesion between the plating layer and the base metal, the coating will peel off from the surface. It is a typical sign of inferior electroplating quality.
6. Local DiscolorationPartial areas of the coating differ from the normal color of the product, such as yellowing, blackening and surface stains.
7. OxidationWhen products are stored for a long time, or the plating layer has poor anti-oxidation performance, the surface will react with substances in the air. This results in rusting, blackening, and even spot corrosion in serious conditions.
8. Plating BurrsDense granular or thorn-like protrusions form on the coating surface, which feel sharp and will scratch gloves when touched.

To eliminate the above electroplating defects, it is essential to strictly control process parameters, optimize the composition of plating solutions and improve the pretreatment quality of base materials. In addition, regular maintenance and inspection of electroplating equipment and plating solutions are equally important. Only in this way can the quality and performance of electroplated products meet the required standards.