Study On The High Temperature Melt Properties Of Zinc Borosilicate Glass Doped With Rare Earth Oxides

This article study the high temperature melt properties of zinc borosilicate glass dopedwith rare earth oxides. The zinc borosilicate glass were prepared with melt annealingmethod. The structure and properties of glasses were characterized by viscometry,dilatometry, differential scanning calorimetry(DSC) and FTIR. The results showed that,For the structure of zinc borosilicate glass, the effect of lanthanum oxide and yttriumoxide has two sides. A small amount of introduction, because of the rare earth ions has thehigh coordination number, high field strength, was in the gap of web and promotes the[BO3] triangle body to convert [BO4] tetrahedron, help network structure became closer.But when the doping amount of rare earth continue to rise, in this article, because Y3+hashigher field strength, lanthanum oxide is more than1.0%, yttrium oxide is more than1.5%,rare earth oxides promote [BO3] and the non bridge oxygen, broken the network, destroyedthe glass network structure, make the structure becomes loose.Lanthanum oxide and yttrium oxide doped lead to changes in the structure of the zincborosilicate glass, affected the melt property of the glass. When a small amount of dopedlanthanum oxide and yttrium oxide, the structure of the zinc borosilicate glass becomeclose, the free volume fraction is reduced, the free volume decreases, viscosity, thermalexpansion coefficient of glass is reduced, kinetic fragility index decreases, and glassformation ability increases.But after doping excessive, the structure of zinc borosilicateglass become loose, with increasing of the free volume fraction and free volume of glass,viscosity decreased, the thermal expansion coefficient of glass increases, kinetic fragilityindex increases, and glass formation ability decreased.In the supplementary experiments, molal composition55ZnO-40B2O3-5SiO2wasselected as the base, using Al2O3replacing B2O3, testing the structure, the thermalexpansion and viscosity of the glass, the conclusion as follows, As Al2O3replaced B2O3, the ratio of B/Al droped, Al3+take free oxygen to form[AlO4] into the network structure, promote the bridge oxygen generated,[BO3] trianglebody with [BO4] tetrahedron linked to form high boron group, make glass structurenetwork gathered together more closely.