KNO_(3)-KCl二元熔盐体系相图的研究

A STUDY ON THE PHASE DIAGRAM OF BINARY SALTS SYSTEM KNO_(3)-KCl

目测变温法,差热分析法,配合X射线粉末相分析研究了KNO_(3)-KCl体系的状态图。体系中有固液异组成化合物KNO_(3)·KCl生成。它在359℃熔化分解为KCl和转熔点液相P。其组成含KCl 12.5Wt%。此化合物在124℃和271℃分别发生两次多晶转变。化合物与KNO_(3)在含KCl 5.0%处形成低共熔点E,其温度为318℃。体系中可能存在介稳化合物4KNO_(3)·KCl,它在342℃熔化分解。

A study has been made of binary salts’system KNO_(3)-KCl by the methods of DTA,visual polythermal and X-ray powder diffraction.An incongruently melting compound KNO_(3)-KCl which decomposes at 359℃andtransittes at 124℃and 271℃has been found in the system.Peritectic point of this compound lies in the composition containing 12.5wt%KCl.The values of the eutectic between KNO_(3)and KNO_(3)-KCl are 318℃and 5.0wt%KCl.Another metastable compound 4KNO_(3)KCl incongruently melting at 342℃may also existes in this system.From the results of DTA and X-ray diffraction,no evidence was found for solid solution on the both sides of KNO_(3)and KCl.