Abstract：To solve the problem of iron oxide yellow pigment being easy to be discolored because of its poor thermal stability, thus affecting its application in plastics processing and other fields, the iron oxide yellow pigment coated with hydroxyl alumina was prepared by the method of precipitation to improve the heat resistance property of iron oxide yellow pigment. The effect of reaction temperature, coating amount and crystallization time on the heat resistance property of pigment was discussed. The structure characterization of the pigment is tested using the technologies of XRD,IR and TG-DTA. The results show that the optimized coating conditions are that the reaction temperature is 80 ℃, coating mass fraction is 15%, and crystallization time is more than 4 h. Under this condition,the heat resistance of the coated iron oxide yellow pigment can reach 240 ℃. The coating phase of iron oxide yellow is hydroxyl alumina. The thermal decomposition of iron oxide yellow pigment coated with hydroxyl alumina is divided into two steps. The endot hermic peak at 245 ℃ is contributed by the heating dehydration of surface hydroxyl alumina, and the endothermic peak at 295 ℃ is contributed by the decomposition of structure water of internal iron oxide yellow.

Keywords: iron oxide yellow; hydroxyl alumina; coating; heat resistance property