−1 . The effect of the synthesis method and that of the size of the phosphate crystallites on the mechanism of polymorphic transition have been discussed. The electric permittivity and dielectric loss measurements were carried out, too. The activation energy of active dipoles in K 3 Nd(PO 4 ) 2 was determined on the basis of the electric permittivity and the dielectric dispersion and absorption measurements
摘要 采用陶瓷法和改良的Pechini 法制备了
钕-
钾磷酸二元β-K 3 Nd(PO 4 ) 2 。使用 TGA/
DSC、XRD、FTIR 和 BET 技术研究获得的粉末。通过 Pechini 方法获得的材料显示出强烈的团聚趋势。在 480°C 下获得的 β-K 3 Nd(PO 4 ) 2 的平均微晶尺寸约为 30 nm。确定了β/α-K 3 Nd(PO 4 ) 2 多晶型转变的温度和焓。对于通过 Pechini 方法获得的材料,多晶型转变发生在 1181 °C,并由一种吸热效应和 Δ H ph.tr 辅助。= 58 ± 9 kJ 摩尔 -1 。对于通过陶瓷技术获得的粉末,β/α 多晶型转变发生在 1148–1180 °C 的温度范围内,并伴随着两个吸热效应,总焓变为 53 ± 15 kJ mol -1 。讨论了合成方法和
磷酸盐微晶尺寸对多晶型转变机理的影响。还进行了介电常数和介电损耗测量。K