阶段升温工艺对SiO2改性Al颜料包覆性能的影响

The Influence of Stage Heating Process on the Properties of SiO Coated Layer of AI Pigments

研究了正硅酸乙酯(TEOS)在片状铝颜料表面水解缩聚形成SiO2包覆膜制备Al颜料的反应过程,重点探讨了两阶段升温变化对包覆性能的影响。FE-SEM和刮板试验结果表明:第一阶段温度50℃,第二阶段80℃时,能在片状铝颜料表面形成一层均匀、致密且遮盖性高、光泽高的SiO2薄膜;EDS和粒径分布测试结果表明:与未包覆的铝颜料相比,SiO2包覆的Al颜料表面硅元素含量增加了1.48%,氧元素含量由1.81%增加到4.60%,SiO2包覆的Al颜料的D50增大了约15%,表明在铝颜料表面形成的SiO2包覆膜非常薄;在pH为9的弱碱性溶液中,220 h后析出的H2体积仅为未包覆铝颜料的2.2%,具有良好的耐弱碱性。

The preparation of SiO2 coated Al pigment by hydrolysis and polycondensation of tetraethyl orthosilicate(TEOS)on the surface of flake aluminum pigment was studied,and the effect of two-stage heating process on the properties of coated layer was discussed in detail.The FE-SEM and scraper test results showed that at the first stage temperature of 50 ℃and the second stage temperature of 80 ℃,a uniform,dense,high coverage and gloss SiO2 layer could be formed on the surface of flake aluminum pigment.The EDS and particle size distribution test showed that,compared with the uncoated Al pigment,the content of silicon in SiO2 coated Al pigment was increased by 1.48%,the oxygen content increased from 1.81% to4.60%,the ratio of Si/Al content was 1.58%,and the d50 of SiO2 coated Al pigment was increased by about 15%,which indicated that the SiO2 coating layer formed on the surface of aluminum pigment was very thin.In the weak alkaline solution with pH value of 9,the volume of hydrogen released after 220 hours of the SiO2 coated Al pigment was only 2.2% of that of the uncoated aluminum pigment,which showed a good weak alkaline resistance.