PHASE-RELATIONS IN THE SYSTEM ZN-GA-S AT 900-DEGREES-C AND 800-DEGREES-C

Phase relations in the ternary system Zn-Ga-S were investigated by dry synthesis at 900 degrees and 800 degrees C, and phase diagrams were obtained for both temperatures. Along the ZnS-Ga2S3 join, there are four solid solutions at both temperatures: (Zn,Ga)(1-x)S, phase V, phase U, and (Ga,Zn)(2)S-3. Along the Zn-Ga join, zinc liquid and gallium liquid coexist at both temperatures, and they have small fields of miscibility. (Zn,Ga)(1-x)S forms an extensive solid-solution. At 800 degrees C, the phase has a mixed sphalerite and wurtzite X-ray-diffraction pattern for all compositions (pure ZnS shows a sphalerite pattern), but at 900 degrees C there is a pattern of sphalerite, wurtzite or a mixture of sphalerite and wurtzite, depending on composition. The mixture is probably metastable, in which case the inversion temperature from the sphalerite form to the wurtzite form must be lower than 800 degrees C. Phase V (tetragonal structure) and phase U (sphalerite structure) have small fields of solid solution at both temperatures.