Non-nickle ion phosphating agent for steel plate processing

Abstract

The invention provides a nickel ion-free phosphating agent for steel plate treatment. The nickel ion-free phosphating agent is characterized by comprising the following matters in percentage by weight: 30 to 50 percent of phosphoric acid, 2 to 5 percent of zinc oxide, 2 to 4 percent of manganese carbonate, 7 to 10 percent of magnesium nitrate, 0.8 to 1.2 percent of cobalt nitrate, 0.2 to 0.4 percent of sodium wolframate, 5 to 8 percent of sodium carbonate and the balance being water. The phosphating agent is used for treating a conversion coating, is quick in phosphating filming, dense in crystallization, good in matching with a cathodic electrophoretic coating, and can reach over 720 hours in a 5 percent of neutral salt spray test. The nickel ion-free phosphating agent is simple in processing, low in product cost and meets the requirement of environmental protection.

Description

technical field [0001] The invention belongs to the field of metal surface chemical treatment, and relates to a nickel-ion-free phosphating agent for steel plate treatment. Background technique [0002] In the process of automobile production, it is necessary to carry out coating treatment on steel plate metal parts, and in the coating process, phosphating treatment is an indispensable pretreatment process. [0003] Phosphating treatment refers to the process of treating metal with an aqueous solution containing phosphoric acid, phosphate and other chemicals, and a chemical reaction occurs on the metal surface to form a complete insoluble phosphate layer with a certain anti-corrosion effect. This layer of phosphate film can prolong the time for the metal to be corroded by the atmosphere, and has a certain corrosion resistance; at the same time, it enhances the adhesion between the metal surface and the coating, as well as the heat resistance and wear resistance of the metal....

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