Zinc paste for Surface Treatment Cr(vi) or Cr-Free
Structure and Anti-corrosion Mechanism of Zinc paste coating
The Basic method of applying the Zinc paste surface treatment is by dip-spin coating or by hanger coating. The degreased parts are cured at the high temperature after dipping in the Zinc paste bath or spraying with Zinc paste solution. The process creates a 5 – 8 µ gray-silver zinc-flake layer on the metallic substrate. Based on the above effect, the anti-corrosion mechanism is extremely efficient in providing anti-corrosion durability. This is due to the combination of passivation on the metallic substrate and the barrier effect of the polymer or zinc and chromic complex.
Characteristics of Zinc paste Surface Treatment
- No wastewater: The Zinc paste surface treatment is dipping-curing process.Therefore, there is no chromic rinsing involved and water cleaning required in Zinc paste Surface Treatment.
- No air pollution: There is no waste air generated in the curing step at the high temperature up to 310℃.
- No waste chemical solution: Zinc paste process is composed of a dry chromic complex bonding metallic zinc flake. However, there is no chemical required in the process.
- Completely free from hydrogen-embrittlement: Acid rinsing and pickling electrolysis reaction are not involved.
- Excellent wetting property: No coating or wetting problem is happened since the Zinc paste process is a dip-spin coating process.
- Excellent corrosion resistance in the salt fog test: Less than 8 µ coating layer shows the best protection during the salt fog test those of zinc electroplating and hot dipping.
- Easy to top color painting: Its products provide an excellent substrate for further color painting.
- High temperature resistance: The products treated by Zinc paste process exhibit the superior corrosion resistance and can be worked in the condition at the temperature up to 250℃.