Solid state diffusion of NaCl into NaY zeolite studied by positron annihilation

Abstract

A series of samples, prepared from mechanical mixtures of NaCl with NaY zeolite and resulting in the dispersion of NaCl in NaY, was studied by position annihila tion spectroscopy. We measured the positron lifetime spectroscopy as a function of the weight ratio of the NaCl-NaY zeolite heated at 500℃ for 1h, as a function of the heating temperature held for 1h, and as a function of the heating duration at 500℃ for NaCl/NaY(15%). All the lifetime spectra were resolved into five components, in which the third, fourth and fifth components are related to the positron annihilation in β cage, supercage and interface void respectively. The experimental results showed that position annihilation spectroscopy is sensitiv e to the change of the dispersion of NaCl in NaY zeolite.