Nonisothermal Crystallization-Kinetic Studies on Ag+ Ion-Exchanged Silicate Glasses: Silver Nanocrystals Growth-Kinetics in Glasses

Abstract

Silver (Ag) nanocrystals (NCs) can be embedded in the glass matrix by simple Na+ to Ag+ ion-exchange (IE) reaction followed by thermal-treatment. We report the nonisothermal crystallization-kinetic studies on the IE silicate glasses by differential thermal analyses (DTA) at different heating rates. Johnson-Mehl-Avrami-Kolomogoroff (JMAK) model was used to examine the crystallization and kinetic behaviour of the NCs grown in glasses. Kissinger and Ozawa models were used to obtain the activation energies for the crystallization. The activation energy obtained from different models are in good agreement. The Avrami kinetic exponent (n) deduced from the kinetic models found to be close to 1. The crystallization-kinetic results indicate the heterogeneous surface nucleation and 1D growth of Ag NCs in the glass matrix. X-ray diffraction, scanning and transmission electron microscopic studies corroborate the crystallization-kinetics results.