The Research Of Preparation And Mechanism On New Non-chromium Dacromet Anti-corrosion Coating

With the whole environmental protection consciousness gradually enhancement, Dacromet coating will be forbidden in not further future because of the hexavalent chromium which can induce cancer. Non-chromium Dacromet coating has been widely applied due to its excellent corrosion resistance, good binding force, no hydrogen brittle and non-pollution.The preparation of non-chromium Dacromet coating solution and anti-corrosion mechanism of non-chromium Dacromet coating were the research focal point. The main components and content of coating solution to the coating performance influence were researched and the optimum formula of coating solution was determined. The operating condition to the coating performance influence was researched and the optimum conditions were determined. The mechanism of coating formation and corrosion resistance were discussed preliminary by using SEM, EDS and XRD. The main results were as follows:(1) The flake zinc powder and aluminum powder were used. For getting fairly good coating outward appearance and increasing the corrosion resistance, the ratio of zinc powder to aluminum powder is 5: 1.(2) The epoxy resin modified by polyurethane was first used as the cementing agent, and the curing agent was polyamide resin. When the mass ratio of epoxy resin modified by polyurethane to polyamide curing agents is 1: 1, the bonding force and corrosion resistance of coating were greatly enhanced.(3) Considered the resin’s dissolubility and the solvent complete volatility degree when roasting, xylene and normal butyl alcohol were used, and its radio is 7: 3.(4) Considered the metal powder’s wettability and dispersivity, the butyl acetate was used as wetting agent.(5) The orthogonal test was designed in which the results were evaluated by the appearance, bonding force and corrosion resistance.