Dilatometric study of the ZnTiO3 phase transition kinetic influenced by nano powder sintering

Abstract

Sintering is often accompanied with phase transition. Phase transition kinetic is thus hard to deconvolute due to the superposition of the sintering and phase transition dimensional change phenomena. Metastabile perovskite phase ZnTiO3 reforms to stabile spinel Zn2TiO4 at 950°C with high kinetic rate. Dimensional change during heating of ZnTiO3 nano powder compacts up to 1050°C was monitored using dilatometric thermo mechanical analyzer TMA model SETSYS Evolution. Shrinkage of simultaneous sintering and phase transition were recorded. The obtained non-isothermally sintered specimens were then second run treated with same schedule. Sintering phenomenon of the ZnTiO3 nanopowder compact was also recorded up to 900°C with isothermal holding of 25 minutes. Here phase transition was avoided with lower temperature and isothermal holding. Second run heating, of isothermally obtained specimens at 900°C, was recorded with non-isothermal heating schedule to 1050°C. This has led to the dilatometric curve record of the ZnTiO3 phase transition in polycrystalline bulk specimen, now recorded without sintering. In such a manner when kinetic is complex, the separation of phenomena such as sintering, linear expansion and phase transition are leading to the knowledge of their mutual interconnected relations. Also application of mathematical operations on dilatometric data leads to the established procedure for the sintering and phase transition data treatment.