铌酸锂钠钾纳米粉体的溶胶-凝胶法合成及其相转变

Preparation and Phase Transformation of(Li_(0.06)Na_(0.47)K_(0.47))NbO_3 Nano-powders Derived from Sol-gel Process

采用化学络合法将Nb2O5转化为可溶性铌盐作为铌源,用溶胶-凝胶法,在500～650℃成功煅烧合成了平均晶粒尺寸为20～60nm的纯钙钛矿相铌酸锂钠钾[(Li0.06Na0.47K0.47)NbO3]无铅压电陶瓷粉体.研究了晶粒尺寸对铌酸锂钠钾纳米粉体相结构的影响.结果表明,基于纳米尺寸效应,随着晶粒尺寸由60减小到20nm,铌酸锂钠钾粉体的相结构由正交相逐渐过渡到四方相,而室温下四方相向立方相的转变将发生在20nm以下。

The pure perovskite （Li0.06Na0.47K0.47）NbO3 lead-free piezoelectric powders were synthesized by the developed sol-gel method, in which Nb2O5 was transformed into a water-soluble niobate by a chemical chelation method as the Nb source. After calcinations at different temperatures between 500 and 650 ℃, the mean particle size of the （Li0.06Na0.47K0.47）NbO3 powders was changed from 20 to 60 nm. The effect of grain size on the phase structure of the （Li0.06Na0.47K0.47）NbO3 nano powders was investigated. The results demonstrated that, as the grain size of the （Li0.06Na0.47K0.47）NbO3 decreased from 60 to 20 nm, the phase structure was transformed from orthorhombic to tetragonal, which can be attributed to the nano-size effect. Further, it can be expected that the tetragonal-cubic phase transition would occur at the size less than 20 nm at room temperature.