Study on the Effect of Pigment/Filler to Binder Ratio on the Performance of 80%Zinc Content Epoxy Coatings
Based on 80%zinc content epoxy coatings and feldspar powder as another auxiliary pigment/filler,four coatings samples with different pigment/filler to binder ratios(1.6,1.7,1.8 and 2.0)near the critical state were prepared.The film forming structure and the anticorrosive property of these samples were investigated.The test results show that with the increase of pigment/filler to binder ratio,the water uptake of tested coatings gradually increases.After 96 h soaking in water,the water uptake of the 2.0 coatings is about 7.8 times that of the 1.6 coatings.The low frequency impedance modulus(Z0.01 Hz)in the Bode plot reduces,and the impedance value of the 1.6 coatings is about 10 times that of the 2.0 coatings,which means that the barrier property of the coatings is weakened.The adhesion of the coatings film decreases after condensation test,salt spray test and heat and humidity resistance test,indicating that the anticorrosive property of the film is reduced.Although the higher the pigment/filler to binder ratio,the lower the price of the coatings,from the perspective that the epoxy zinc-rich primer should have good anticorrosive property and pursue cost-effectiveness on this basis,the pigment/filler to binder ratio is recommended to be no higher than 2.0,to ensure that the coatings still show excellent adhesion(not less than 5 MPa)after the anticorrosive test.
pigment/filler to binder ratioepoxy zinc-richanticorrosive propertyadhesion
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