| Vacuum glazing is an energy saving building material with excellent thermal insulation performance,which is widely used in building curtain walls and so on.The production technology of vacuum glazing involves materials science,packaging,vacuum technology and other fields.Among this,packaging technology is an important part of the industrialization of vacuum glazing,however packaging material is the base of the packaging technology.Low melting point glass as a packaging material with low cost,low sealing temperature,high sealing strength and good sealing performance that is widely used in electronic packaging and its products.Development of low melting point glass with excellent performance could avoid the failure of low-e film and the annealing of toughened glass at high temperature in vacuum glazing.At the same time,the use of anode bonding technology to assist the vacuum glazing packaging,reduces further the vacuum glazing sealing temperature,so it is important to study for the good performance of low melting point glass.At present,the main development direction of sealing glass is composed of lead-free,sealing low temperature,glass microcrystalline.In this paper,the vanadate system low melting point glass was studied,and applied melting method to prepare V2O5-P2O5-B2O3 lead-free low melting glass.The structure and properties of the glass were researched by means of thermal expansion,differential scanning calorimetry,infrared spectroscopy and X ray diffraction.And the best glass composition was chose.The suitable viscosity of glass paste was evenly coated on the surface of substrate glass by a screen printing method.The sealing experiments were carried out in the heat treatment furnace and bonding furnace respectively,through Shear Strength test,Super-depth Microscopy,Scanning Electron Microscopy and Energy Spectrum to determine the best heat treatment schedual and explore the feasibility of vacuum glazing sealing technology with assisting anodic bonding.The main results are as follows:1)The Vanadate low melting point glass was chose for which the glass transition temperature is 350?400?and the expansion coefficient is matched with the substrate glass,the percentage of mass per component is:V2O5 4065%,P2O52030%,TeO2 15%,B2O3 12%,RO 17%,R2O 13%.2)With the increase of P2O5 in the glass composition,the glass expansion coefficient increases first and then decreases,while the glass transition temperature and the softening temperature show the opposite trend.This phenomenon is show that[PO4]tetrahedral stick into the[VO3]n chain structure,decreasing the structure strength of the glass,resulting in the expansion coefficient increases,the glass transition temperature Tg and softening temperature Tf are reduced.With the increase of[PO4]tetrahedron in the glass,the structure of the chain vanadate decreases and the structure of the layered vanadate increases,which makes the glass network structure firmness increase,the glass thermal expansion coefficient decreases and the glass transition temperature Tg and Softening temperature Tf increases.3)The sealing temperature of V2O5-P2O5-B2O3 system glass was determined by flow column experiment,the glass was melted at 400?,and the working temperature was 420460?.4)Suitable viscosity glass paste was deployment,and the slurry was coated with screen printing.After adding diethylene glycol butyl ether,to ensure the quality of printing and save the material,the effect of the 3 layer is the best.5)Through the shear strength test to determine the best sealing temperature of low melting point glass is 470?,when the holding time is 30min,the bonding strength reaches 2.655MPa.The influence of heat treatment process for the sealing performance was investigated by means of surface morphology observation.6)To determine the best anode bonding process,when the voltage applied which can effectively reduce the sealing temperature.When the voltage reaches 600V that meet the requirements of bonding,the voltage continues to increase will lead to glass breakdown cracking.When the bonding temperature is 470?,the voltage is 600V,the sealing sample air tightness is 3.9×10-9Pa·m3/s which meet the sealing requirements. |
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