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

The effect of chlorine on the structure of AlF ₃ /YF ₃ ‐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 BaCl ₂ 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‐u Cl _u ] polyhedra remains a low constant value. In the high BaCl ₂ content region (>6 mol %), the chlorines replace more fluorines in the already formed [AlF _n‐u Cl _u ] polyhedra and do not attack other [AlF] polyhedra, while the composition of [YF _m‐v Cl _v ] polyhedra does not change.