Effect of Chloride on the Structure of Fluoroaluminate Glasses Studied by XPS

The effect of chlorine on the structure of AlF₃/YF₃-based fluoride glasses was studied by XPS. The changes in the bonding state of cations with increase of chlorine content were all investigated by measuring the composition-depend- dent changes in the relative concentration and binding energy of related cations. It was proposed that the chlorine replaces the bridging fluorine by which the AlF _n ] and YF _m ] polyhedra are connected and result in the formation of AlF _n-u Cl _u ] and YF _m-v Cl _v ] polyhedra. In the low BaCl₂ content region (<6 mol%), as many chlorine as possible attack A1FJ and YF _m ] polyhedra, and with the increase of chlorine content, they replace more fluorines in YF _m ] polyhedra, while the number of chlorines in AIF_n-uCl_u] polyhedra remains a low constant value. In the high BaCl₂ content region (>6 mol %), the chlorines replace more fluorines in the already formed AlF_n-uCl_u] polyhedra and do not attack other AlF] polyhedra, while the composition of YF_m-vCl_v] polyhedra does not change.