| Environmental protection has been included in China’s national development objects, and will become the pronoun of all kinds of newly sprouted things. Research findings of non-oriented silicon steel environmental friendly coating emerge one after another; however, there are little systematic research about it. This paper systematically studies solution formulations optimization and curing process optimization of non-oriented silicon steel chromium-free insulation coating. Especially the study of curing process is groundbreaking in the industry, which has certain theoretical guiding significance for the curing process of silicon steel industrial production.Preliminary formulation of non-oriented silicon steel chromium-free insulation coating was conclude with orthogonal test and evaluated by solution stability, corrosion resistance, adhesion and appearance of coating. The best formulation was56%aluminum dihydrogen phosphate by dry weight,4.0%zinc oxide by dry weight,9.7%boric acid by dry weight,29.4%acrylic resin by dry weight, a small amount of composite additives and appropariate amount deionized water. The resulting coating exhibited excellent insulation, corrosion resistance and adhesion, which comprehensive performance is comparable to chromate coating. Further, the influence of different contents of zinc oxide, boric acid, arylic resin on performance of coating was studied by salt spray test, electrochemical test, adhesion test and surface morphology. And this paper explored the coating formation mechanism of phosphatic non-oriented silicon steel insulated coating. At high tempertures, coating dehydration condensation reaction occurs to form a glass film layer with complex three-dimensional mesh structure, which has excellent insulation and barrier propterty to silicion steel matrix.Lastly, there was a systematic research about the curing process of chromium-free non-oriented silicon steel insulation coating which was studied in the form of the combination of theoretical analysis and experimental validation. The thermal analysis of coating shows that the coating occurred complete curing between260℃and320℃. Further, a testing apparatus of coated plate temperature vs time was designed and manufacutured to measure the changes of the actual temperature of the coated non-oriented silicon steel sheet over time at different curing temperatures so as to obtain process curve of the coated plate temperature and curing time. Salt spray test, electrochemical experiment, adhesion test and surface morphology were used to verify that the process curve was reasonable and could be used to guide the research of chromium-free non-oriented silicon steel insulating coating the curing process of silicon steel production line. |
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