1100 2000广 1000 1500 o ExperimeinL --.DoCD 900 16t0 1·2 800 5 】400 一I23 L14'u0 1200 9 700 NdaXJ2Cu L》 1100 600 (L0 800- 20 40 60 80 100 500L 0 Nd2O3 Cuo 20 1o% 60 100 Na2B204 kI320 mol Fig.3 Phase diagram of Nd203 Cuo Fig.4 Phase diagram of Na2B204-K2B204 Taking Na2B2O-K2B2O system as another sample example. 2.1 Experimental Determination of the Na2B204-K2B20,Phase Diagram The phase diagram of Na2B2O,-K2B2O,binary system was firstly deter- mined by means of DTA and X-ray diffraction methods.Just shown in Fig.4, it is a complete solid solution system with minimum melting point at Tm= 836C and Xmin=0.357mol K2B2O.In the figure4."denotes the top temperature of melting peak in DTA curve,4."denotes the extrapolated onset temperature of melting peak.The available results agreed well with those obtained by refe- rencest,).But,the miscibility gap shown in Fig.4 could not be observed using DTA and room temperature X-ray diffraction technique by both Bergman and ourself. 2.2 Computer Calculation of the Na2B20,-K2B20 Phase Diagram Liquidus can generally be determined more accurately than solidus because of the hysteresis of phase transition.Kohler and Pelton suggested a method to calculate solidus from liquidus if the enthalpy and excess entropy of liquidus phase as well as either the enthalpy or excess entropy of the solid phase were known.To apply the method to molten salt system CmXp-DnXr,it is more convenient to introduce ionic fractions Yi and equivalent fractions Zi for representing ideal mixing entropy and excess quantities,respectively. 157〔 【 — 目 」 ， 了 ‘ 匕宁 七》七 、 、 叮乙 一 厅 、 户 汉 川 扮 ， 汉获杯 厂 与 幻 吸 忿 匕 。卜卜 日 【 上 「 土汽 〔 「 丫 别 匕 〔 通 今 一… 了 一 、 位 一 ‘ 一 ‘ 。 ， 一 一 、 一 。 ， 。 ， 。 。 ‘ ， “ 一 ， ， “ 。 ” · 〔 ’ 。 〕 ， 一 几 。 。 ‘ 一 。 · 一 ， 住 币 ，