Chrome plating is often used for visible appearance parts that need to be visually attractive. Chrome surfaces have a very decorative white, slightly bluish color and are very resistant to corrosion. Components made of steel, high-quality steel and copper, aluminum or zinc alloys can be chrome plated. If chrome-plated plastic is desired, the material that can be chrome-plated is acrylonitrile butadiene styrene (ABS), but we do not chrome-plate aluminum and plastic at the KNK zamac plant.
Depending on the base material, chrome plating is preceded by grinding and polishing and multiple coatings of copper and nickel that add smoothness and shine to the subsequent layer of chrome, which has a consistent blue-white color that is resistant to abrasion due to its hardness, allowing the shine to be maintained over time and during its regular cleaning. The final layer consists of approximately 0.3-0.8 μm of chromium. Depending on the process, different surfaces can be created: matte chrome plating, pearlescent gloss plating, shiny chrome plating and black chrome plating, while at the KNK zamac plant we make matte and shiny hexavalent chromium.
At the KNK zamac plant, we mainly chrome our zinc alloy die castings, and for a perfect mirror shine, it is essential to maintain the following operations:
1. Grinding, fine grinding/satining and polishing
2. Degreasing in the case of external metal parts and pickling
3. Electroplating copper plating
4. Polishing and repeated degreasing
5. Electroplating copper plating and subsequent nickel plating
6. Electroplating chrome plating
Degreasing takes place in a closed cycle of the EcoClean device from the manufacturer Durr, where the cleaning medium is Isopar H in combination with ultrasound and steam.
Electroplating chrome is a very time-consuming surface treatment method, but it achieves very high corrosion protection, a high level of hardness and abrasion resistance (reduces friction), temperature resistance up to approximately 300 °C and a very decorative surface, but not every component geometry or material is suitable for this process. Consult us!
| Galvanization type | Used Passivation | Corrosion resistance | Environmental compliance | Main applications |
| Electroplating with Cr3+ Passivation | Trivalent chromium (Cr3+) | Good | High | Automotive, Electromechanical |
| Electroplating with Cr6+ Passivation | Hexavalent chromium (Cr6+) | Excellent | Low value | Critical industrial applications |
| Chrome-free galvanization | Chrome-free passivation | Moderately | Maximum value | Electronics, telecommunications |
If the nickel layer under the chrome is dull, then the surface will still be dull (dull chrome) after it is bright chrome plated. This type of dull surface is sometimes required to avoid glare – reflections of light, while maintaining the required hardness, and we at KNK zamac call it satin.
