Kinetics and Mechanism of the Interaction of Alkali Calcium Silicate Glasses with Salt Melts in the KNO_3-Pb(NO_3)_2 System

摘要

The interaction of alkali calcium silicate glasses with salt melts in the KNO_3-Pb(NO_3)_2 system is investigated at temperatures of 420-520 deg C.The chemical composition of crystalline coatings formed upon treatment contains both components of the initial glass (SiO2,9-12 wt %;CaO,0.8-1.2 wt %) and components of the salt melt (PbO,82-89 wt %).The treatment temperature is the main factor affecting the structure of the modified surface layer.The mechanism of the interaction of alkali calcium silicate glasses with salt melts is analyzed.According to this mechanism,the interaction involves the ion exchange (with the participation of Na~+,K~+,Ca~(2+),and Pb~(2+) ions),crystallization of modified surface layers,and incorporation of Pb_xO_y nanoparticles (formed in the salt melt) into the coating structure.