Positronium decay study of zirconia-silica sol-gels

Positron annihilation lifetime (PAL) and Doppler broadening of annihilation line (DBAL) techniques have been used to investigate the fine-pore structu re of the system xZrO(2) . (1 - x)SiO2 (x = 4, 10 mol%). The samples were p repared by the alkoxide method of sol-gel process. The influences of the et hanol/alkoxide ratio and the heat-treatment on the pore structure have been studied. Pores of two different sizes, R similar to 3 Angstrom and R simil ar to 9-11 Angstrom were measured in the samples studied. It was establishe d that the heat-treatment had greater influence on the defect structure tha n the ethanol/alkoxide ratio, for both ZrO2 contents. (C) 2000 Elsevier Sci ence B.V. All rights reserved.