PHASE DIAGRAMS OF THE BINARY SYSTEMS TbCl3-MCln(M=Li,Mg,Ca,Pb;n=1 or 2)
(Peking University; Beijing 100871; China)
Abstract: The phase diagrams of the binary systems RECl3-MCln(M=Li,Mg,Ca,Pb;n=1 or 2)were investigated by means of DTA and X-ray diffraction analysis.It was found that they are of simple eutectic type with eutectic points 50.1 Mol.-% TBCl3(445℃),67.5Mol.-% TbCl3 (589℃),65.9Mol.-% TbCl_(563℃)and 35.6 Mol.-% TbCl3(445℃)respectively.Unstable compounds,formed in the solid slate,are MgTbCl7,CaTb2Cl8,LiTb2Cl7 and PbTbCl5.Their decomposition temperatures are 388℃ with a phase transition at 352,500 and 521℃ with a phase transition at 483 and 405℃ respectively.Some rules of the phase diagrams were explored.
Key words: TbCl3; TbCl3-LiCl; TbCl3-MgCl2; TbCl3-CaCl2; TbCl3-PbCl2; system phase diagram Rule of phase diagram