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The control of dacromet coating’s temperature

Posted on 2018-03-21
The use of dacromet coating, most companies' standard mesh belt furnace heaters control the preheat zone temperature 80~120℃。The main purpose of this heating is to evaporate the moisture in the coating without boiling,at the same time, it is certainly accompanied by a chemical process of reduction of hexavalent chromium by alcohol.

 

The method for this determination is a mixture of pure Dacromet B (aqueous chromic anhydride) and polyethylene glycol reductant in proportion. The coating was baked on a glass slide and heated at 120°C for 15 minutes. The water was evaporated and the remaining substance was a dark green wet film.

 

If the test piece is heated to 120 minutes, the color of the coating becomes bright green, and the coating becomes hard, but it can be washed away with water. Obviously, it is not possible to use a long-term heating at 120°C to operate a coating of Dacromet.