Study On Structure And Crystallization Of Advanced Borate Glass

Low-melting sealing glass and rare-earth doped bismuth borate glass are the important systems of advanced borate glasses. Recently, the studies on advanced borate glasses are focused on developing and realizing new glass systems, few reports were found on the mechanism of glass formation and the relationship between glass structure and properties. Based on the mechanism of glass formation and glass network structure, studies on compositional effects of glass structure and properties should be an available work to understand and forecast properties of advanced borate glasses and consequently have a significant influence on the design and applications of advanced borate glasses.In this work, series of PbO-B₂O₃ glass, Bi₂O₃-B₂O₃ glass, lead borate sealing glass and rare-earth doped bismuth borate glass were prepared by melting-quenching method. Combined with the glass structure and crystallization properties of binary borate glass systems, compositional effects on glass thermal stability, mechanical properties and other properties of advanced borate glasses were investigated.The results of FTIR and Raman analysis indicate that PbO only acts as a network modifier of PbO-B₂O₃ glass in the compositional range of 10 mol%≤PbO≤20mol%, with the further increase of PbO, it tends to play as a glass former. In the system of Bi₂O₃-B₂O₃ glass, Bi₂O₃ was one of the glass former. Three possible structure models and two possible structure models were suggested to explain the effects of PbO and Bi₂O₃ on borate glass networks respectively.Both PbO and B₂O₃ are the important components of low-melting sealing glass. Therefore a series of lead borate sealing glasses with different ratios of PbO/B₂O₃ were designed. Based on the structure and crystallization analysis of PbO-B₂O₃ glass, effects of PbO/B₂O₃ and additive oxides (including ZnO, Bi₂O₃, GeO2) on sealing temperature, thermal expansion property, chemical stability and mechanical property of lead borate sealing glasses were involved. Two successful batches of low-melting sealing glass were obtained named G3 and BL10. The sealing temperature of G3 glass is 400℃, which is 40℃lower than that of commercial sealing glasses. The PbO content of G3 is 54mol% (as the same as in commercial sealing glass) and no toxic component is involved. The sealing temperature of BL10 glass is similar to that of traditional sealing glass (440℃), while the PbO content is decreased to...