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....

AI Technical Summary

Problems solved by technology

But adding nickel salt has two disadvantages: one is high cost; the other is that environmental protection is restricted. Nickel ion is unfavorable to environmental health and environmental protection, and its discharge is strictly limited. It can activate or inhibit a series of enzymes to exert its toxicity, causing damage to the lung, liver, brain, etc., and may increase the incidence and mortality of lung cancer, gastric cancer, paranasal sinus cancer, and cause great harm to the human body

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