EFFECT OF PHASE TRANSFORMATION ON OPTICAL PROPERTIES OF ZNTIO3 CERAMIC POWDER PREPARED BY SOL-GEL METHOD

Abstract

ZnTiO3 powders were prepared by sol-gel method using ammonium hydroxide. The effects of calcination temperature (500– 1000∘ C). and the molar ratios ZnO/TiO2. The synthesis of a nano perovskite ZnTiO3 usually results in the formation of one or more of the compounds such as Zn2TiO4, and ZnTiO3 with other secondary impurity phases such as rutileTiO2 or ZnO. To obtain a phase-pure a nano perovskite ZnTiO3 at a low processing temperature is one of the challenges in materials chemistry., pure ZnTiO3 can not be synthesized under normal conditions, because it transforms into Zn2TiO4 and rutile. In the current study, the crystalline and phase transformation behaviors of sol-gel synthesized a nano perovskite ZnTiO3 has systematically been investigated with regard to various Zn:Ti precursor molar ratios. The ZnTiO3 phase can be detected by XRD in the powders calcined above 600 °C. The formation of ZnTiO3 is a slow reaction process, which leads to the development of large ZnTiO3 particles, with dimensions after calcination at 700 °C for 5 h in the range of 68–81 Nm. Calcination temperature increased considerably the crystallite size of the nano perovskite ZnTiO3 from 68 to 81 nm This treatment led also to the creation of holes in the matrix of calcinated solids which increased the mobility of charge carriers (electrons) leading to a significant decrease in the decrease in the optical energy gap reaching to (2.7 to 2 )e.v.