Study On The Structure And Properties Of ZnO-BaO-B₂O₃-SiO₂ System Glass

Belonging to the series of the borosilicate glass,ZnO-BaO-B₂O₃-SiO₂ system glass had the advantages of low cost,wide applicability,good chemical stability,etc,which was used as the sealing glass and sintering aiditive.As a new one,this system glass could be increased in the type of the sintering aids.To a certain extent,it made up the shortcomings of the relatively higher sintering temperature and sealing temperature for the series of the borosilicate glass to meet more performance requirements of various industries for sealing glass and sintering additive.In this paper,putting BaO、ZnO、B₂O₃ and SiO₂ as the basic components,the ZnO-BaO-B₂O₃-SiO₂ system of glass could be perpetrated by adjusting the content of each component or adding P₂O₅ and TiO₂ to the basic components to be used for sealing at low temperature and being as sintering additive,and its structure and properties were detailed studied.By changing the content of ZnO,the content ratio of B₂O₃/SiO₂ and the addition amount of P₂O₅ and TiO₂ in the glass,it was studied that the effect of the content changing of each component on the glass structure and the glass properties such as the density,thermal expansion coefficient,temperature characteristics,chemical stability and sintering property,etc.The regular of the influence on the properties of glass by changing the content of each oxide was got by comparative analysis.The TiO₂ containing glass was dealied with nucleation and crystallization to study the influence of crystallization time on the system glass of crystallization type and morphology etc.The target was to explore the operability for the.quaternary system to turn into glass-ceramic.The result shows that,the ZnO-BaO-B₂O₃-SiO₂ system glass is manufactured by the method of high temperature melt cooling,and it has the good performance to be as the lead-free sealing glass and the sintering aidditive.The structure of the quaternary system glass is relatively stable when the ZnO content is between 2～10wt%and the content of B₂O₃ and SiO₂ are kept invariant.The subject of the glass is constituted by[SiO₄]and[BO4]tetrahedral.The CTE varies from 57.30×10-7℃^-1 to 63.29×10-7℃^-1 and the glass has the effect of sintering additives and sealing glass.The CTE and the transition temperature（Tg）show a tend of decreasing on the whole.The larger micro-hardness and better chemical stability are obtained in the glass containing ZnO 6wt%.Remaining the content of ZnO and BaO unchanged,as the result of the B₂O₃/SiO₂ ratio increasing,the glass density and the using temperature for sealing are decresing,the micro-hardness becomes better,the chemical stability is worse,and the CTE appears maxima and minima.The CTE of the glass is adjusted by changing the ratio of B₂O₃/SiO₂,so that it matches the expansion coeffient of metal to seal together.The increase of the P₂O₅ content leads the sintering temperature to rise,and the coefficient of themal expansion tends to increase.P₂O₅ fills the structure of the glass and reduces the coefficient of themal expansion when its content is less than 1.5wt%.The increase of the TiO₂ content results in a increase trend of CTE,but it does not much mipact on the transition temperature and softening temperature.The crystallization ability is improved by TiO₂ in a certain extent.The glass has the effect of sealing glass under 800 ℃and being sintering additives in the process of ceramic sintering.The TiO₂ crystals are got by the crystallization treatment on the 5Ti02^-15Zn0-24Ba0-33.6B₂O₃-22.4SiO₂ system glass.As the crystallization time prolonging,the TiO₂ crystals grow,which is the shape from spherical into needle.In addition to the TiO₂ crystal,there is no other crystal in the glass.The TiO₂ crystal particles agglomerated when being crystallization for 18h.