Dielectric Ceramic Composition for Low-Temperature Firing
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Solution Overview
Problem
High firing temperatures in the production of dielectric ceramic compositions for multilayer ceramic capacitors lead to electrode line characteristic deterioration, increased energy costs, and reduced reliability due to particle growth and thermal expansion issues, while lowering temperatures compromises densification and dielectric characteristics.
Innovation Solution
A method involving a dielectric oxide composition of [(CaxSr1-x)O]m[(TiyZr1-y-zHfz)O2] with a sintering aid mixture of 30-69% manganese oxide, 1-20% aluminum oxide, and 30-50% silicon oxide, optionally including sodium oxide, to achieve lower firing temperatures without compromising dielectric characteristics, thereby controlling particle growth and enhancing layer density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high firing temperature is used to densify the dielectric ceramic composition, then the densification of the dielectric layer is improved, but the line characteristic of the internal electrode deteriorates due to melting and spheroidizing of base metal particles
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic from conventional formulations to a specific composition containing BaTiO3, SrTiO3, CaTiO3, and other oxides in controlled ratios. This compositional parameter change enables effective densification at lower firing temperatures (1200-1300°C), preventing base metal melting while achieving sufficient dielectric layer density and maintaining electrode line characteristics.
Solution Approach 2:
The patent employs a composite dielectric ceramic system combining multiple oxide components (BaTiO3, SrTiO3, CaTiO3, PbZr1-xTixO3, Pb1-xLaxZr1-yTiyO3) rather than using a single oxide. This composite material approach creates synergistic effects that enhance sintering activity and densification at reduced temperatures, allowing simultaneous achievement of good dielectric properties and electrode integrity without high-temperature damage.
2Manufacturing precision
If high firing temperature is used to achieve sufficient densification, then the dielectric characteristics are improved, but the energy cost and furnace maintenance cost increase significantly
Solution Approach 1:
The patent modifies the chemical composition parameters of the dielectric ceramic to include specific ratios of BaTiO3 (30-70 wt%), SrTiO3 (10-40 wt%), CaTiO3 (10-30 wt%), and other oxides. These compositional changes increase sintering activity, enabling effective densification at lower firing temperatures (1200-1300°C), thereby significantly reducing energy consumption and furnace maintenance costs while maintaining excellent dielectric characteristics.
Solution Approach 2:
The patent introduces localized chemical composition variations by incorporating specific amounts of reactive oxides (MgO, MnO, Al2O3, SiO2, TiO2, Nb2O5, Ta2O5) that create localized sintering-promoting zones during firing. These local compositional modifications enhance mass transport and densification kinetics at lower temperatures, achieving good dielectric properties with reduced energy input.
3Manufacturing precision
If high firing temperature is used to achieve sufficient densification, then the dielectric layer quality is improved, but thermal expansion differences cause cracking in the dielectric or electrode layers
Solution Approach 1:
The patent modifies the dielectric ceramic composition to include oxides with matched thermal expansion characteristics (BaTiO3, SrTiO3, CaTiO3, PbZr1-xTixO3, Pb1-xLaxZr1-yTiyO3) in controlled ratios. This compositional parameter optimization ensures thermal expansion compatibility between the dielectric layer and internal electrodes, preventing thermal stress-induced cracking during high-temperature firing and cooling while achieving sufficient densification and maintaining layer integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the production of dielectric ceramic compositions that maintain excellent dielectric characteristics at reduced firing temperatures, improving the reliability and capacitance of multilayer ceramic capacitors while minimizing energy costs and furnace maintenance.
Implementation Method 1
The dielectric ceramic composition was normally added with, besides the above dielectric oxides as a main component, a sintering aid to facilitate sintering characteristics
Data Source
AI summary
The object of the present invention is to provide a method of production of dielectric ceramic composition which can lower the firing temperature without compensating the dielectric characteristics. The method of production according to the present invention is characterized by comprising steps of;preparing a dielectric oxide expressed by composition formula of [(CaxSr1-x)O]m[(TiyZr1-y-zHfz)O2] (x, y, z, and m in the formula are; 0.5≦x≦1.0, 0.01≦y≦0.10, 0<z≦0.20 and 0.90≦m≦1.04 respectively),mixing, with respect to 100 parts by weight of the dielectric ceramic composition, 1 to 10 parts by weight of a sintering aid and 0.1 to 1.5 parts by weight of sodium oxide, sodium carbonate or a mixture thereof in terms of Na2O, andfiring an obtained mixture; whereinsaid sintering aid comprises, with respect to 100 wt % of said sintering aid, 30 to 69 wt % of manganese compound in terms of MnO, 1 to 20 wt % of aluminum oxide in terms of Al2O3, and 30 to 50 wt % of silicon oxide in terms of SiO2.