【摘要】 本文用X射线衍射、热处理及差热分析等方法测定了SrNb₂O₆-NaNbO₃-LiNbO₃赝三元系的室温截面及相应的SrNb₂O₆-NaNbO₃,SrNb₂O₆-LiNbO₃和NaNbO₃-LiNbO₃等三个赝二元系相图;粗略地研究了Sr_0.42Na_0.16NbO₃-LiNbO₃系的纵截面;含5mol％LiNbO₃及10mol％LiNbO₃的SrNb₂O₆-NaNbO₃的纵截面。确定了室温Sr₂Na（NbO₃）₅（以下略为S₂N）相为四方钨青铜结构。其点阵常数为a=12.36,c=3.906.LiNbO₃在S₂N相内的溶解度可达～10mol％,当LiNbO₃含量超过5mol％时,S₂N相畸变为S₂N相。S₂N相为正交晶系。实验确定室温S₂N（S₂N）相系亚稳相。在900-1100℃长时间退火即分解为SrNb₂O₆和以NaNbO₃为基的固溶体的混合物。更多还原

【Abstract】 The pseudo-ternary system SrNb206-NaNbO3-LiNbO2 has been investigated by means of DTA, heat treatment and X-ray diffraction techniques. It has been found that at room temperature Sr2Na(NbO3)5(S2N) is a metastable intermediate compound which has a tetragonal tungsten-bronze structure with a=12.36 A, c=3.906A. LiNbO3 can be dissolved in S2N up to a limit about 10 mol% ; and in the range of 5-10mol% of LiNbO3, the S2N phase is distorted into S2N’, which belongs to the orthorhombic system and is also a metastable phase. After long time annealing at 900-1100℃, the metastable phases S2N, S2N’ will decompose into a mixture of SrNb2O6 and a phase of solid solution based on NaNbO3. The phase diagram of the corresponding binary systems and the isothermal section of the pseudo-ternary system have been established.更多还原