Preparation And Properties Study For The Corrosion Resistance And Anti-fouling Coatings On The Heat Transfer Surface Of The Carbon Steel

Heat exchanger is one of the widely used equipments in the daily life and industrial and agriculture production. According to the survey,90%of the heat exchangers has different degrees of corrosion and fouling problems. The presence of corrosion and fouling shorten the service life, lower the heat transfer capacity and increases the medium flow resistance of the heat exchanger. At present, most of the heat exchangers use carbon steel as the material, and usually because of the environmental corrosion, fouling of the material, heat transfer, fluid erosion and other complex environments, the corrosion and fouling is a very serious problem.This project will deposit Ni-Cu-P alloy coatings on the heat transfer surface by electroless plating to improve the corrosion resistance and anti-fouling of the surface. The test has determined the best formulation and process conditions of the electroless deposition Ni-Cu-P coatings, analyzed the influence of plating liquid composition and process parameters towards to deposition rate and corrosion resistance. Also, by means of combination test, XRD, SEM, EDS to study the combining force, organizational structure and composition of the coatings.The test also adopts the method of polarization curves, AC impedance and fouling deposition to study the corrosion resistance and anti-fouling of the Ni-Cu-P alloy coatings. Use heat treatment furnace to heat the plated Ni-Cu-P alloy coatings at different temperature and theoretically analyze the composition structure and corrosion resistance of the coating after heat treatment.Experimental researches and theoretical analysis show that the best plating liquid composition and process conditions for electroless deposition for Ni-Cu-P alloy coatings are NiSO425g/L, CuSO40.50g/L, NaH2PO235g/L, Na3C6H5O745g/L, NaCH3COO15g/L, an appropriate amount of thiourea, pH=6, T=85℃.The coating is a kind of cellular amorphous structure with the average composition of73.69%Ni,13.29%Cu and13.01%P. The comparison tests for corrosion resistance and anti-fouling performance and heat treatment of the coatings indicate the Ni-Cu-P alloy coatings have good corrosion resistance and anti-fouling performance after200℃heat treatment.