Study On High Strength CaO-Al₂O₃-SiO₂ Sealing Glass And Its Coloring

In this thesis,CAS（CaO-Al₂O₃-SiO₂）system is taken as the research object.Referring to the predecessor glass formula,the ternary phase diagram is made to obtain the best base glass.On the basis of the best base glass formula,B₂O₃ and Li₂O were doped to adjust the thermal and mechanical properties of the glass.The high-strength glass powder used for sealing alumina and zirconia ceramics and its coloration were studied.The experimental results are as follows:（1）Experiment with 85.4%（xCaO-yAl₂O₃-zSiO₂）-13.6%（Na₂O+K₂O）-1%（TiO₂+MgO）system:Glass can be formed in the range of x=1⁴%,y=19²2%,z=77⁸0%.The glass component in the ternary phase diagram was tested to obtain the best matrix component as the G6 sample,which had the best glass structure,and its composition was x=2%,y=20%,and z=78%.The thermal expansion coefficient,the glass transition temperature,and the three-point bending strength were respectively:8.5×10^-6/°C,T_g=603.9°C,70MPa.（2）When B₂O₃ was doped with the composition of G6 sample,it was found that with the increase of B₂O₃ incorporation,the boron-oxytetrahedral[BO₄]group gradually formed in the network structure of the glass,which enhanced the strength of the glass network;The transformation temperature is gradually reduced,the density is gradually increased,the mechanical properties are gradually enhanced,the thermal expansion coefficient is gradually reduced,and the thermal expansion coefficient can be adjusted from 8.1 to 8.5×10^-6/°C,the bending strength increases from 70MPa to77.95MPa.Analumina ceramicfor sealing having a thermal expansion coefficient of7.86×10^-6/°C was prepared by solid phase method at 1550°C,and the shear strength after sealing was gradually increased from 9.47MPa to 24.78MPa..（3）When Li₂O was doped with the composition of G6 sample,it was found that with the increase of Li₂O incorporation,the glass network structure first strengthened and then weakened,the glass transition temperature of the glass sample decreased continuously,and theΔT of the glass increased first and then decreases.The bulk density of the glass sample first increases slightly and then decreases,and the glass softening temperature decreases continuously;the three-point bending strength first increases and then decreases,the max bending strength was obtained at 4mol%Li₂O,76.03MPa.The leucite was prepared by the solid phase method,and leucite was added to the glass frit to obtain an adjustable thermal expansion coefficient in the range of 9.8-11.6×10^-6/°C.A zirconia ceramic having a thermal expansion coefficient of 10.66×10^-6/°C was prepared by solid phase method and coprecipitation method at1480°C.The shear strength of the glass increases as the incorporation of leucite increases from 36MPa to 46MPa.（4）Calcining aluminum-iron red,cobalt blue andZirconium-praseodymium yellow raw materials at 1000°C to 1250°C:The crystal phase and color of aluminum-iron red sample A3 obtained after sintering at 1100°C;CoAl₂O₄ of C5 sample obtainedat1250°C;ZrPrO₄ of Z1 sample obtained at 1100°C.Their crystal phase and color are optimal.With the increase of the content of aluminum-iron red and zirconium praseodymium yellow material,the b* value of the sample gradually increases;the two colorants have opposite effects on the L*value and the a* value,and the aluminum-iron red decreases the L* and increases the a* value,and its effect is more significant than that zirconium-praseodymium yellow;the incorporation of zirconium and hafnium yellow material makes the effect of increasing the b* value of the glass sample more significant;the three-point bending strength of the glass sample first increases and then decreases.The synergistic effect of aluminum iron red and zirconium-praseody yellow on the color of glass:the content of fixed aluminum-iron red material,with the increase of the content of zirconium praseodymium yellow material,the L* value of the sample first increases and then decreases;the sample a* value first decreases,then increases;the b* value of the sample keeps increasing.The content of the fixed zirconium praseodymium yellow material decreases with the increase of the content of aluminum-iron red material.The a* value of the sample increases continuously;the b*value of the sample increases continuously.