Abstract: Nanometer TiO₂ powders were prepared by four different methods. DSC and TG techniques were used to study the changes of TiO₂ compositions and phases from 25℃ to 900℃. The gels powders of TiO₂ were characterized by XRD and TEM. DSC and TG results show that the absorbed water and organism will be lost at 80～100℃, the organism discompose at 280～290℃, TiO_２ thus obtained will transform from amorphous phase to anatase phase, at 370～400℃, the structure water will be lost above 500℃, and anatase phase transform gradually to rutile phase between 650℃ and 900℃.

Key words: TiO₂ nanometer powder, thermal analysis, lost weight ratio