Effect of Cr2O3-Y2O3-MgO Ternary Sintering Aids on Microwave Dielectric and Insulation Properties of 99%Alumina Ceramics
99%alumina ceramics doped with Cr2O3-Y2O3-MgO were prepared by pressureless sintering at temperatures of 1 480 ℃,1 500 ℃,1 530 ℃,and 1 550 ℃.The effects of varying doping amounts of Cr2O3 on the densification,microstructure,microwave dielectric properties,and insulation properties of the 99%alumina ceramics were studied.The results show that appropriate amounts of Cr2O3,Y2O3,and MgO can promote sintering,reduce intergranular voids,improve density,and enhance overall performance.Under the conditions of w(Cr2O3)=0.4%,w(Y2O3)=0.24%,w(MgO)=0.16%,and sintering temperature of 1 530℃,the ceramics exhibit a density of 3.919 cm3,a dielectric constant(εr)of 9.985,a dielectric loss(tanδ)of 0.000 5,and a breakdown voltage of 25.3 kV.The doping of Cr2O3 improves the microwave dielectric and insulation properties of the 99%alumina ceramics,showing promising potential in electronic packaging materials.
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