二氧化钛表面包覆氧化铝的形态和机理分析

采用分光光度法研究了三氧化二铝的pH-吸光度（A）曲线，确定了铝的沉积pH范围为4.0～10.5；研究了沉积pH和沉积时间对产品颜料性能的影响。采用XRD分析了三氧化二铝在不同pH条件下沉积的晶型，在酸性条件下沉积为无定型，碱性条件下沉积为勃姆石型；还研究了不同pH下沉积的三氧化二铝的比表面积，结果表明在碱性和酸性条件下，三氧化二铝比表面积分别为69.71 m²/g和37.80 m²/g。采用电子能谱对二氧化钛样品表面结构进行表征，2p电子轨道结合能的变化表明铝以Al-O-Ti键的形式结合在二氧化钛表面。

Analysis on morphology and mechanism of TiO2 surface coated with Al2O3

The pH-absorbency （A） curve of Al₂O₃ was studied by spectrophotometric method.The pH range of aluminum deposition was confirmed at 4.0~10.5.Influence of the deposition pH and deposition time on the product′s pigment properties was investigated.Crystal forms and specific surface area of Al₂O₃  at different pH were also investigated.The crystal types of Al₂O₃  deposited at different pH conditions were analyzed by XRD.Results showed the crystal type of Al₂O₃ deposited under acidic condition was amorphous，and under alkaline condition was boehmite type.The specific surface areas of Al₂O₃  deposited at different pH were also studied，which were 69.71 m²/g and 37.80 m²/g under alkaline and acidic conditions，respectively.XPS was used to characterize the surface structure of titanium dioxide samples.According to the change of 2p orbital electron binding energy of Ti in XPS，it could be inferred that Al in coating layer combine onto TiO₂ surface through Al-O-Ti bonds after being coated.