Protective Performance of Waterborne Inorganic Zinc Shop Primers after Short-Term High Temperature Treatment

D1510 H and D1610 two waterborne inorganic zinc shop primers with different compositions were sprayed on the low-carbon steel plate or PET film, and short-term(3 min) high temperature treatments at different temperatures(400, 600, 700, 800 ℃) were carried out. The protective performance of two shop primers was studied by thermogravimetric differential scanning calorimetry analysis, outdoor exposure test and neutral salt spray test. The results show that after short-term high temperature treatment, both of the two shop primers had residual metal zinc indicating they had a certain protective performance. D1510H shop primer had high inorganic content; the shop primer had dense surface structure after high temperature treatment at 800 ℃, and still had good outdoor protective performance; the shop primer was suitable for the protection of large steel structures with short processing cycle and subsequent partial surface treatment measures. D1610 shop primer had high content of organic matter and metal zinc, and had loose surface structure after high temperature treatment at 700,800 ℃, but could withstood high temperature treatment at 600 ℃; it was suitable for the protection of substrates with long processing cycles and subsequent comprehensive secondary rust removal.