| Low-melting glass powder has the advantages of low melting temperature,high sealing mechanical strength and good chemical stability,and is widely used in many fields such as microelectronics technology,electric vacuum,and automobiles.The bismuth silicate glass system is currently the most practical system for replacing toxic lead glass.The traditional tantalate sealing glass is mostly melt-quenched.The lanthanide glass powder is used as a basic material for sealing or connecting materials.The glass powder has high transparency and good gas after sintering.Tightness and heat resistance,and also have better corrosion resistance and electrical insulation.Therefore,it is used as a fluxing and bonding agent,glass ink,electronic paste sintering,sealing and packaging of electronic components.Very important position.In this thesis,Bi2O3-SiO2-B2O3 lead-free glass powder was used as the research object,and it was prepared by melt-quenching method.The effect of Bi2O3 on the structure and properties of glass powder was studied.The microstructure and particle size of the glass powder were observed by SEM.The network structure of the glass was analyzed by IR and Raman test.The amorphous phase and crystal phase of the glass powder were analyzed by XRD,and the glass powder was determined by Bi2O3.The influence law of the network structure;the characteristic temperature of the glass powder was tested by DSC.The flow diameter and the wetting angle of the cylinder sample were calculated by sintering experiments,and the flow and wettability of the glass sintering were characterized.The coefficient meter tests the thermal expansion of the glass powder,and the influence of Bi2O3 on the sintering performance of the glass is proved.The viscosity and fluidity of the glass paste are tested by the rotary rheometer,and the solid content of the slurry and the glass powder are proved.The effect of the content of Bi2O3on the viscosity and fluidity of glass.The main research contents and results are as follows:1.The influence of Bi2O3 on the micro-morphology and particle size of glass powder was investigated.The glass powder particles showed near-spherical morphology after 20 h high-energy ball milling,and the particle size ranged from 1 to 5?m.With the increase of Bi2O3,the particle size of the glass powder gradually decreased and the particle size gradually became uniform.2.The influence of Bi2O3 content on the structure of glass network was determined.The glass network structure is mainly composed of[BiO6]octahedron,[BiO3]triangle,[SiO4]tetrahedron,[BO4]tetrahedron and[BO3]triangle.As the content of Bi2O3increases,the[BiO3]triangle in the glass structure The number of bodies and[BO3]triangles is reduced,the number of[SiO4]tetrahedrons remains basically unchanged,and the glass network structure mainly exists in the form of high distribution.The coordination number is large,the binding energy is low,and the glass structure is unstable.The glass has a crystalline state.Part of the crystal phase precipitates,and high coordination makes the particles densely arranged,and the mechanical strength of the glass is high.The base glass powder has a typical amorphous structure,and a crystal phase exists when the content of Bi2O3 is large.3.The effect of Bi2O3 content on the characteristic temperature of glass was investigated.With the increase of Bi2O3 content,the characteristic temperatures Tg and Ts of glass show a downward trend,and finally tend to be gentle.The glass transition temperature Tg ranges from 444 to 466?,and the glass softening temperature Ts ranges from 495 to 513?.When the Bi2O3 content in the glass was increased to 70%,the glass transition temperature Tg was 444?,and the glass softening temperature Ts was 513?.4.The influence of Bi2O3 on the sintering properties and thermal expansion of glass was investigated.When the sintering temperature is higher than 550?,the surface of the glass sample is smooth,and the sintering process mainly shows three shapes of cylindrical shape,hemispherical shape and flattening.As the content of Bi2O3 increases,the diameter of the glass sample increases,the wetting angle decreases to 41°,and the sintering dispersibility and wettability increase.After sintering,the surface of the glass sample gradually flattens and the density increases.The thermal expansion coefficient?25350??of glass samples varies from 6.96 to 7.86×10-6/K.With the increase of Bi2O3mass in glass,the thermal expansion coefficient tends to increase.When the content of Bi2O3 in the glass is 70%,the coefficient of thermal expansion is 7.786×10-6/K.5.The influence of slurry solid content and glass powder Bi2O3 content on glass viscosity and fluidity was investigated.The solid viscosity is 82%and the minimum viscosity is 0.4 Pa·s.As the content of Bi2O3 in glass powder increases,the viscosity of glass samples decreases gradually.The minimum viscosity is 13.6Pa·s,when the content of Bi2O3 is 70%.The fluidity of glass samples decreased with the increase of solid content;with the increase of Bi2O3 content of glass powder Increased,but the anti-settling ability of the slurry becomes weak. |
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