Cailiao Baohu (Aug 2023)
Preparation and Performance Characterization of Zinc Silicate-Potassium Silicate Waterborne Anticorrosive Paint
Abstract
In order to solve the problems of volatile organic compounds (VOC) and easy aging of organic solvent based anti-corrosion coatings commonly used for reinforcing steel bars in autoclaved aerated concrete (AAC) plates，waterborne inorganic silicate anti-corrosion coatings were prepared by using modified high-modulus potassium silicate solution，zinc silicate powder and additives.The influence of zinc silicate content on the workability，adhesion and bonding strength of the coating was studied.The chemical composition，phase composition，and microstructure of the coating were characterized，and the anti-corrosion performance of the coating was analyzed.Results showed that the bonding strength of the paint gradually decreased with the increase of the zinc silicate content.And the adhesive strength increased first and then decreased as increasing the content of zinc silicate.When the content of zinc silicate was 50% (mass fraction)，the paint exhibited superior physical，mechanical and anti-corrosion properties due to the suitable ratio of film-forming material to pigment and filler.The adhesion and bonding strength were 3.9 MPa and 1.8 MPa，respectively.Moreover，after immersion in the solution with 3.5%NaCl for 7 d，the open circuit and polarization resistance of the paint were -221 mV，39 470 Ω·cm2，respectively.The flat and smooth paint，the passivation film on the surface of the substrate，and the relatively dense hydrated calcium silicate at the interface between AAC and the coating provided a good physical shielding for the substrate.
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