Synthesis and evaluation of Pb1-xSnxF2 by mechanical milling

Pb1-xSnxF2(x=0.2-0.6) solid solutions were synthesized by mechanical milling (MM) from a mixture powder of alpha-PbF, and SnF2. It was clarified that the solid solutions were synthesized not by heat but by the kinetic energy of the milling balls. For x=0.2-0.6 except for x=0.5, the mixtures changed to Pb1-xSnxF2, which has the iso-structure of beta-PbF2. Furthermore, for x=0.5, the mixture changed to PbSnF4. The crystallinity of the synthesized solid solutions using MM was improved by annealing at 200-500 degrees C, which is much lower than the maximum temperature at which the solid solution of Pb1-xSnxF2 (x<0.23) was synthesized using a melting method. The Pb0.8Sn0.2F2 solid solution synthesized by MM showed a fluoride ion conductivity equal to that of the solid solution synthesized using a melting method. The fluoride ion conductivity of the pressed powder sample of the solid solution synthesized using MM increased with x from 0.2 to 0.5, showed a maximum of 1.6 x 10(-3) S/cm at x=0.5 at room temperature, and decreased with increasing x of more than 0.5. After annealing the pressed powder, the fluoride ion conductivities of solid solutions for x=0.5 showed the high values of 3 x 10(-2) S/cm at room temperature and 0.34 S/cm at 150 degrees C. (c) 2005 Elsevier B.V. All rights reserved.