Dielectric Ceramic Composition for Mid-High Voltage Capacitors
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Solution Overview
Problem
Existing dielectric ceramic compositions for multilayer ceramic capacitors, especially those used in mid-high voltage applications, face challenges with low withstand pressure and insufficient lifetime characteristics, leading to reliability issues when downsizing and increasing capacitance.
Innovation Solution
A dielectric ceramic composition comprising specific ratios of BamTiO2+m, BanZrO2+n, Mg oxide, rare-earth oxides, and oxides of Mn, Cr, Co, Fe, Si, Li, Al, and B, which can be fired in a reducing atmosphere, reducing electrostriction and improving capacitance-temperature characteristics and insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dielectric ceramic composition is used for downsizing and increasing capacitance in mid-high voltage applications, then capacitance and miniaturization are improved, but withstand pressure and lifetime characteristics deteriorate, leading to reliability issues
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of multiple oxide components in the dielectric ceramic. Specifically, it uses BamTiO2+m with m=0.99-1.01, BanZrO2+n with n=0.99-1.01, along with specific amounts of Mg oxide (4-12 moles), rare-earth oxide (4-15 moles), transition metal oxide (0.5-3 moles), and other oxide (3-9 moles) per 100 moles of BamTiO2+m. This compositional parameter optimization enables the dielectric layer to maintain high breakdown voltage and insulation resistance even when downsized, resolving the contradiction between capacitance increase and reliability maintenance.
Solution Approach 2:
The patent employs composite materials by combining multiple oxide components with complementary properties. The dielectric ceramic composition integrates BamTiO2+m (providing high permittivity), BanZrO2+n (enhancing stability), Mg oxide (improving sintering), rare-earth oxide (boosting electrical properties), and transition metal oxide (controlling grain growth). This multi-component composite structure achieves synergistic effects that simultaneously improve capacitance, withstand pressure, and lifetime characteristics, even in downsized capacitors operating at mid-high voltages.
2Volume of moving object
If the dielectric layer is made thinner to downsize the capacitor, then device size is reduced, but reliability of the capacitor deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the chemical composition parameters of the dielectric ceramic to compensate for the reduced thickness. By adjusting the ratios of BamTiO2+m, BanZrO2+n, and additive oxides within specific ranges, the material achieves enhanced breakdown voltage and electrical stability that offset the weakening effect of thinner dielectric layers, maintaining reliability despite downsizing.
Solution Approach 2:
The patent uses composite materials with a multi-oxide formulation that provides superior electrical properties. The combination of Mg oxide, rare-earth oxide, and transition metal oxide in the dielectric composite creates a material structure with improved charge trapping, reduced leakage, and enhanced breakdown strength, allowing thin dielectric layers to maintain high reliability in downsized capacitors.
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
The composition enhances withstand pressure, accelerated lifetime of insulation resistance, and maintains good specific permittivity, enabling the production of highly reliable multilayer ceramic capacitors suitable for mid-high voltage applications while allowing for downsizing and increased capacitance.
Implementation Method 1
a dielectric ceramic composition, able to be fired in a reducing atmosphere
Implementation Method 2
fired in a reducing atmosphere
Implementation Method 3
less in electrostriction when applying a voltage
Data Source
AI summary
The invention aims at providing a dielectric ceramic composition including BamTiO2+m where “m” satisfies 0.99≦m≦1.01 and BanZrO2+n where “n” satisfies 0.99≦n≦1.01, an oxide of Mg, an oxide of R where R is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, an oxide of at least one element selected from Mn, Cr, Co and Fe, and an oxide of at least one element selected from Si, Li, Al, Ge and B. 35 to 65 moles of BanZrO2+n, 4 to 12 moles of an oxide of Mg, 4 to 15 moles of an oxide of R, 0.5 to 3 moles of an oxide of Mn, Cr, Co and Fe, and 3 to 9 moles of an oxide of Si, Li, Al, Ge and B are included therein per 100 moles of the BamTiO2+m.