Abstract: 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.

Key words: titanium dioxide, alumina, surface coating