Al（OH）3@Zn（OH）2双层包覆氧化铁黄合成及其耐热性能研究

采用共沉淀法对铁黄颜料进行Al（OH）₃/Zn（OH）₂双层异相包覆,提升其耐热性能,并通过XRD、TG-DTA、FT-IR、SEM&EDS等手段对包覆前后铁黄颜料的微观结构进行表征。研究结果表明,包覆质量分数为40%的Al（OH）₃时铁黄颜料的耐热性能较好;第二层包覆Zn（OH）₂,最优包覆质量分数为30%,样品在240 ℃时色差值为1.84。XRD测试结果表明,Al（OH）₃和Zn（OH）₂包覆并没有改变氧化铁黄的特征峰,两者可能以无定形态包覆在铁黄粒子表面。SEM、EDS、FT-IR测试表明,Al（OH）₃/Zn（OH）₂已成功对铁黄颜料进行了包覆;此外,还出现了片状结构对应Al（OH）₃自身成核现象,包锌后出现了团聚现象。TG-DTA表征显示,包覆后样品升温脱水分两步,低温吸热峰对应包覆层物质的脱水,高温吸热峰偏向更高温度,对应包覆颜料耐热性能的提升。

Study on preparation and heat resistance of iron oxide yellow coated with double layer Al(OH)3@Zn(OH)2

The iron oxide yellow pigment was coated with double layer heterogeneous Al（OH）₃/Zn（OH）₂ by coprecipitation method to improve its heat resistance.The microstructure of iron oxide yellow pigment before and after coating was character-ized by XRD,TG-DTA,FT-IR,SEM & EDS technologies.The research results showed that the heat resistance of iron oxide yellow pigment coated with 40% of Al（OH）₃ was better,and the optimal coating amount was 30% when the second layer was coated with Zn（OH）₂,and the color difference of the sample was 1.84 at 240 ℃.XRD results showed that coating of Al（OH）₃ and Zn（OH）₂ did not change the characteristic peak of iron oxide yellow,and they may be coated on the surface of iron oxide yellow in amorphous form.SEM,EDS and FT-IR tests showed that Al（OH）₃/Zn（OH）₂ had successfully coated the iron yellow pigment.In addition,the flake structure was corresponding to the nucleation of Al（OH）₃ itself,and the agglomeration occured after zinc hydroxide coating.TG-DTA characterization showed that the sample with coating was heated and dewatered in two steps.The low temperature endothermic peak was corresponding to the dehydration of the coating material,while the high temperature endothermic peak tended to higher temperature,which was corresponding to the improvement of the heat resistance of the coating pigment.