FORMATION OF A SURFACE LAYER OF MULTICOMPONENT LEAD-SILICATE GLASSES IN HYDROGEN ON HEATING

摘要

X-ray electron spectroscopy and thermodynamic analysis are used to investigate the sequence of chemical transformations of the elements of a surface layer of silicate glass in the system PbO - BaO - Na_2O - Al_2O_3 -- SiO_2 under heating in a hydrogen atmosphere. The process of thermal reduc?tion of a multicomponent lead-silicate glass in hydrogen is a multistage process of diffusion and chemical in?teraction of lead with hydrogen. Reduction of lead is observed, the lead atoms bound with aluminum-oxygen groupings interacting being the first to interact with hydrogen after which the lead atoms in the silicon-oxygen structural units interact with hydrogen. The remaining components of the glass do not interact with hydrogen in the temperature range 375 -475 deg C. The concentration profiles of the elemental distribution in the surface layer of the reduced glasses are determined.