SrTiO_3-SrZrO_3 solid solution: Phase formation kinetics and mechanism through solid-oxide reaction

摘要

The perovskite solid solution composition Sr(Ti_(0.5)Zr_(0.5))O_3 (STZ (ss)) has been synthesized from the mixture of SrCO_3, TiO_2 and ZrO_2 powders through solid-state reaction. The phase formation mechanism and kinetics were investigated using TG/DSC, XRD. SrCO_3 in the precursor decomposes at relatively lower temperature than pure powder decomposition, due to the presence of acidic TiO_2. Upon calcinations of the precursor SrTiO_3 (ST) and SrZrO_3 (SZ) were formed separately in the system. Then ST defuses in to SZ to form STZ (ss). ST formation started at lower temperature (800℃) with lower activation energy (47.274 kcal/mol) than SZ. SZ formation started at 1000℃ with high activation energy (65.78 kcal/mol). STZ (ss) formation started from 1500℃ with very high activation energy (297.52 kcal/mol). It is concluded that solid solution formed coherently with SZ lattice by the diffusion of Ti in to the SZ.