用XRD法系统地研究了PFN-PMN二元系中钙钛矿相的前驱体FeNbO4（FN）-MgNb2O6（MN）煅烧过程中的物相变化。发现,富镁的前驱体混合物在较高的煅烧温度下有富镁的Mg4Nb2O9（M4N）生成,而富铁的前驱体混合物中FN的生成,有利于抑制M4N的形成.M4N的形成与钙钛矿相煅烧产物中烧绿石相的出现有密切的关系.在MN与FN二种前驱体中,MN在大约650℃时即开始生成,而FN则需至800℃才开始生成,表明较低温度下Fe2O3的反应活性不及MgO的反应活性。
The phase development in the calcination of the precursors for the pseudo-binary system of PFN-PMN was investigated systematically by XRD method. During the
calcination of Mg-rich mixtures, a kind of Mg-rich niobate, Mg4Nb2O9 forms along with the major phase MgNb2O6 (MN), whereas in the
calcination of Fe-rich mixture, there is no Mg4Nb2O9 formed, indicating Fe2O3 (or FeNbO4) may inhibit the formation of
Mg4Nb2O9. The appearance of Mg4Nb2O9 is directly related to the formation of pyrochlore in the calcinations of perovskite. MN starts to form at a temperature as
low as 650℃, a temperature much lower than its ferric counterpart FN. Therefore the reactivity of Fe2O3 is inferior to that of MgO in
the low temperature region.
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