碱金属碘酸盐赝二元系固溶体的研究

碱金属碘酸盐形成的二十一个赝二元系中,六个体系为机械混合物,九个体系是形成化合物的(其中三个是离子化合物),其余六个体系形成连续固溶体。本文对KIO₃-NH₄IO₃,RbIO₃-NH₄IO₄等赝二元系形成的连续固溶体进行了研究。NH₄IO₃中加入KIO₃或RbIO₃时,随加入量增加,NH< 关键词：

INVESTIGATION OF THE SOLID SOLUTIONS IN ALKALI- METAL IODATE PSEUDO-BINARY SYSTEMS

Among the 21 pseudo-binary systems formed by alkali-metal iodates (including HIO₃ and NH₄IO₃), there are 9 in which compounds can be synthesized in aqueous solutions or by powder-sintering, 6 which are mixtures of the constituents; and the rest of the systems can formed continuous solid solutions. The pseudo-binary systems KIO₃-NHJO₃, RbIO₃ etc. were studied by means of thermal analysis (DTA, TG) and Xray diffraction, and were found to be of continuous solid solutions. With addtion of KIO₃ or RbIO₃, the phase transition temperature of NH₄IO₃ is decreased and its decomposition (at the same time burning) temperature is raised; the room temperature phase of NH₄IO₃ (monoclinic) is transformed gradually into cubic phase with increasing content of KIO₃ or RbIO₃. Samples in the binary systems with NH₄IO₃ as a component exhibit good pyroelectric property. In this paper, the stability and the change of lattice parameter with compositions of the solid solutions that were found in alkalimetal iodate binary systems were also discussed.