| Abstract: | Some halogen-doped calcium borate glasses containing iron have been prepared according to the precentage molar composition [(30-X)CaO · xCaX2 · 10 Fe2O3 · 60 B2O3)] and annealed. Scanning electron micrographs of heat-treated glasses show that the microstructure consists essentially of two phases. By introducing the halogen ion one of the primary phases (Ca-rich borate) decreases in its volume and a new phase appears and exists as crystalline form. A secondary phase can also be produced which segregates in Ca-rich borate as droplets. Magnetic susceptibility, molar volume, and infrared measurements revealed that at concentrations of CaX2 < 10 mol% the halide ions may be introduced as modifiers and as network formers at CaX2 concentrations > 10 mol%. |
