Carbon steel, galvanized plate and aluminum material same-trough surface pretreating agent, preparation method and metal surface pretreatment method

The invention discloses a carbon steel, galvanized plate and aluminum material same-trough surface pretreating agent, a preparation method and a metal surface pretreatment method. The surface pretreating agent comprises, by mass, 0.6%-1.2% of silane coupling agent, 2.43%-4.725% of fluozirconic acid, 0.4%-0.8% of anhydrous sodium sulphate, 0.2%-1.2% of sodium citrate, 0.2%-0.8% of borax, 0.1%-0.2% of caustic soda flakes, 9%-18% of magnesium salt, 1%-4% of aluminum salt, 3%-6% of ethyl alcohol, and the balance deionized water. The treating agent is capable of saving energy and protecting environment, simple in process, low in cost and suitable for pretreatment of carbon steel, zinc materials, hot galvanized plates, electro-galvanized sheets, and aluminum and aluminum alloy materials before coating, and can allow same-trough treatment, effectively increase the binding force between coatings and a substrate and improve the corrosion resistance of a coating system.