Effect Of P₂O₅, Fe₂O₃ And Sb₂O₃ On Structure And Property Of Bi₂O₃-ZnO-B₂O₃ Glasses

Due to low glass transition temperature and appropriate thermal expansion coefficient,bismuthate glasses can be applied as sealing materials for electronic components,electric vacuum device and plasma display panel.However,with big content?50⁸0 wt %?and higher price of Bi₂O₃,bismuthate glass cost much.As a heavy metal oxide,Bi₂O₃ has a higher density leading to bismuth glass easy to segregation,which limited their engineering applications.Therefore,it has important theoretical significance and application value to improve its performance by replacing Bi₂O₃ with P₂O₅,Fe₂O₃,Sb₂O₃ etc.,in bismuthate glasses.Bi₂O₃-ZnO-B₂O₃-RnOm?RnOm=P₂O₅,Fe₂O₃,Sb₂O₃?system glasses were prepared by traditional melt-quenching method.The glass structure was investigated by Fourier transform infrared spectroscopy?FTIR?,Raman spectroscopy?Raman?,nuclear magnetic resonance spectrum?NMR?and X-ray diffraction method?XRD?.Thermal properties were characterized by differential scanning calorimetry?DSC?and thermal expansion instrument,including transition temperature?Tg?,initial crystallization temperature?Tc?,thermal stability,thermal expansion coefficient???and soft temperature?Ts?.Density was tested by the Archimedes method and water resistance was studied by weight loss method.The results were as follows:The scope of the substitution of P₂O₅ for Bi₂O₃ content has been determined.It was observed that the glass formed a uniform and stable glass system with 0 to 15mol% P₂O₅.After Bi₂O₃ was replaced by P₂O₅,P₂O₅ presents as a network former in the network structure of the glass.The O-P-O linkages symmetric stretching vibration appeared while there is no P=O linkages in the glass network,indicating the formation of P-O-B.The network structure was strengthened due to the cross-link between the phosphorus oxygen polyhedron and the boron oxide polyhedron,thus improved glass structure.The relative content of [BO₃] increased,while the relative content of [BO₄],[BiO₃] and [BiO₆]decreased.When the content of P₂O₅ was 0 to 5 mol%,thermal stability become worse and the content was 7.5 to 15 mol%,it turned well.Density and thermal expansion coefficient decreased with the increasing P₂O₅ contents,whereas the tendencies of transition temperature and soft temperature varied contrarily.Water resistance was improved.The scope of the substitution of Fe₂O₃ for Bi₂O₃ content has been determined.It was observed that the glass formed a uniform and stable glass system with 0 to 10mol% Fe₂O₃.After Bi₂O₃ was replaced by Fe₂O₃,it was observed that Fe₂O₃ presents as a network modifier in the network structure of the glass.The relative content of [BO₃] increased,while the relative content of [BO₄],[BiO₃] and [BiO₆] decreased.When the Fe₂O₃ content was 0 to 2.5mo%,thermal stability did not significantly reduced,and the content was 5 to10mo%,it reduced sharply.Density and thermal expansion coefficient decreased with the increasing Fe₂O₃ contents,whereas the tendencies of transition temperature and soft temperature varied contrarily.When the Fe₂O₃ content was 0 to 2.5mol%,water resistance was improved sharply,and the content was 5 to 10mo%,it was improved smoothly.The scope of the substitution of Sb₂O₃ for Bi₂O₃ content has been determined.It was observed that the glass formed a uniform and stable noncrystalline glass with 0 to 2.5mol%or 15 to 25mol%.After Bi₂O₃ was replaced by Sb₂O₃,Sb₂O₃ presents as a network former in the network structure.The Sb-O linkages asymmetric stretching vibration and Sb-O-Sb linkages antisymmetric stretching vibration appeared on the glass network.The relative content of [BO₃] increased,while the relative content of [BO₄],[Bi O₃] and [BiO₆]decreased.When the Sb₂O₃ content was 0 to 2.5mol%,thermal stability improved and transition temperature increased.When the Sb₂O₃ content was 15 to 25mol%,thermal stability firstly decreased and then increased.At 17.5mol%,thermal stability was the worst,transition temperature was the highest.Density and thermal expansion coefficient decreased with the increasing Sb₂O₃ contents,whereas the tendencies of soft temperature varied contrarily.When the Sb₂O₃ content was 0 to 2.5mol%,water resistance improved.When the content was 15 to 25mo%,firstly increased and then decreased.At 17.5mol%,water resistance was the best.