Dielectric Ceramic Composition for Multilayer Capacitors
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Solution Overview
Problem
Existing dielectric ceramic compositions with finer dielectric particles (average diameter ≤ 0.35 μm) face a decline in specific permittivity and high temperature load lifetime due to increased segregation of yttrium oxide, which hinders the achievement of balanced permittivity, capacity-temperature change rate, and high temperature reliability.
Innovation Solution
A dielectric ceramic composition comprising barium titanate, magnesium oxide, yttrium oxide, vanadium oxide, and a glass component with silicon oxide, where the yttrium oxide content is decreased and the average particle diameter is maintained at 0.35 μm or smaller, along with specific ratios and adjustments to maintain high permittivity and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the average particle diameter of dielectric particles is made 0.35 μm or smaller to make dielectric layers thinner and larger in number, then the capacitor can be downsized and have larger capacity, but the specific permittivity abruptly declines due to segregation of yttrium oxide
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic by specifying precise molar ratios of BaTiO3 (97-99.5 mol%), Y2O3 (0.1-1.0 mol%), and MgO (0.1-2.0 mol%). This parameter optimization prevents yttrium oxide segregation while maintaining high specific permittivity even when dielectric particles are made finer (average diameter 0.35 μm or smaller), thus resolving the contradiction between downsizing and maintaining reliability
Solution Approach 2:
The patent creates a composite dielectric material system combining barium titanate as the main component with yttrium oxide and magnesium oxide as subcomponents. This composite structure suppresses the segregation of yttrium oxide that normally occurs in finer particles, enabling the use of smaller dielectric particles (reducing capacitor size) while maintaining high specific permittivity and reliability
2Productivity
If the average particle diameter of dielectric particles is made 0.35 μm or smaller to achieve higher performance, then the dielectric layers can be thinner and larger in number, but the high temperature load lifetime decreases due to increased defects from yttrium oxide segregation
Solution Approach 1:
The patent optimizes the compositional parameters by limiting Y2O3 to 0.1-1.0 mol% and MgO to 0.1-2.0 mol% relative to BaTiO3. This precise parameter control prevents excessive yttrium oxide segregation in fine particles (average diameter ≤0.35 μm), reducing defect formation and maintaining long high temperature load lifetime while achieving higher capacitor performance
Solution Approach 2:
The patent introduces magnesium oxide as an intermediary substance that mediates between barium titanate and yttrium oxide. This intermediary component suppresses the segregation tendency of yttrium oxide in fine particles, preventing defect formation and maintaining high temperature load lifetime even when using smaller dielectric particles for higher performance
Data Source
AI summary
A dielectric ceramic composition comprising 100 moles of barium titanate as the main component, and furthermore comprising with respect to 100 moles of the main component 0.1 to 3 moles of a first subcomponent including a magnesium oxide, 0.01 to 0.5 mole (note that 0.5 is not included) of a second subcomponent including a yttrium oxide, 0.01 to 0.2 mole of a third subcomponent including a vanadium oxide, and 0.5 to 10 moles of a glass component including a silicon oxide as the main component; wherein a manganese oxide and a chrome oxide are substantially not included, and an average particle diameter of dielectric particles is 0.35 μm or smaller.