Nickel Electrode The X7r Anti Restore The Development Of The Ceramic Material

BaTiO3－based dielectrics doped with acceptor type ions or rare earth ions such as Ca2+,Na+,Mg2+,Mn2+,Y3+,Dy3+and Co3＋have been studied in this thesis. The dielectrics are co-fired with nickel electrode in a reducing atmosphere. The solubility or segregation of these ions and their effects on the properties of the ceramic dielectric are discussed, especially, the relationships between the different manufacture processes and the electrical properties of the ceramic are systematically investigated. Nanometer vitreous additives are composed by sol-gel technique, which can form perfect "core-shell" structure when doped in BaTiO3.So the desirable properties of ceramic dielectric can be obtained, such as the reduction of dissipation factor, the broad of Curie peak and the enhancement of dielectric constant. The basic composition of this kind of dielectric can be expressed as the following formula: (BaO)mTiO2+αY2O3+β[Mn(1-x)Cox]O+ w[Na2(1-y-z)+Mgy+Caz]O)n·SiO2 0.01≤α≤0.03,0.004≤β≤0.01,0.02≤w≤0.05,0.03≤x≤0.09,0≤y<1,0≤z<1,0.8≤y+z≤1,1≤m≤1.035,1≤n≤2The dielectric behaviors of this anti-reduction ceramic reach the level as follows when firing at optimal sintering condition: ε25℃≥3000,ρ≥1011Ωcm,tgδ≤1.5%, Eb(V/mm)≥(8KV/mm)[DC],Eb(V/mm)≥(3.6KV/mm)[AC],ΔC/C25℃(-55℃—+125℃)≤±15%,the temperature dependence of dielectric constant can well satisfy the X7R specification.