铝包膜TiO2的膜层结构对颜料性能的影响

Influence of film structure of aluminum-coated TiO2 on the properties of pigments

摘要:

以偏铝酸钠为包膜剂，采用液相沉淀法在TiO2粒子表面包覆Al2O3膜。采用TEM、SEM、XRF等手段表征无机膜层，通过测试包膜TiO2样品的耐候性、光泽度、亮度等评价其颜料性能。研究以HRTEM结合晶格计算分析膜层氧化铝晶型，并对包膜pH和温度对包膜TiO2的膜层结构和颜料性能的影响进行了实验研究。结果表明，酸性条件下包膜TiO2的膜层氧化铝为无定形，样品耐候性较优；pH=10时膜层氧化铝为勃姆石型和拜耳石型混合晶型，以勃姆石型为主，产品颜料性能优异；pH>11时膜层氧化铝为拜耳石型，产品颜料性能较差。温度升高会增加膜层氧化铝的结晶度，提高包膜TiO2产品的颜料性能。

关键词:二氧化钛;氧化铝膜;晶格间距;晶型;颜料性能

Abstract:

The surface of TiO2 particles is coated with Al2O3 film by liquid-phase precipitation method and sodium metaaluminate as coating agent. The inorganic film layer was characterized by TEM, SEM, XRF and other means, and its pigment performance was evaluated by testing the weather resistance, gloss and brightness of the coated TiO2. The alumina crystal form of the coating layer was analyzed by HRTEM combined with lattice calculation, and the effects of coating pH and temperature on the coating layer structure and pigment properties of the coating TiO2 were experimentally studied. The results show that the film layer of alumina coated with TiO2 is amorphous under acidic conditions, and the sample has better weather resistance; when pH=10, the film layer of alumina is a mixed crystal form of boehmite and bayerite, with boehmite type Mainly, the product has excellent pigment performance; when pH>11, the alumina film layer is Bayerite type, and the product pigment performance is poor. Elevated temperature increases the crystallinity of aluminum oxide in the film layer and improves the pigment properties of the TiO2 samples.

Key words:titanium dioxide; aluminum film;lattice spacing;crystal form; pigment properties