BaTiO3 Dielectric Ceramic Composition for MLCC Temperature Stability
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Solution Overview
Problem
Current dielectric ceramic compositions for multilayer ceramic capacitors face challenges in achieving high specific permittivity and small temperature change of capacitance, with existing materials like barium titanate exhibiting large temperature-dependent capacitance and insufficient crystallinity.
Innovation Solution
A dielectric ceramic composition is developed comprising BaTiO3, Y2O3, MgO, V2O5, and additives such as MnO, Cr2O3, CO2O3, {Baα, Ca (1−α)}SiO3, and minor components like Sr, S, Al, Fe, Zr, and Hf, optimized in specific ratios to enhance specific permittivity and reduce temperature change, while maintaining high insulation resistance and crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barium titanate (BaTiO3) is used to increase specific permittivity, then specific permittivity is improved, but temperature change rate of capacitance becomes large
Solution Approach 1:
The patent uses a composite dielectric ceramic system consisting of BaTiO3 as the main component combined with multiple oxide additives (Y2O3, MgO, V2O5, MnO, Cr2O3, Co2O3) and silicate compounds ({Baα, Ca (1−α)}SiO3). This composite approach allows the material to achieve high specific permittivity from BaTiO3 while the additives work together to stabilize the capacitance temperature characteristics by controlling phase transitions and reducing thermal expansion differences.
Solution Approach 2:
The patent optimizes the compositional parameters by precisely controlling the ratios of BaTiO3 (86.32 to 97.64 mol%), Y2O3 (0.01 to 10.00 mol%), MgO (0.01 to 10.00 mol%), and other additives. By adjusting these compositional parameters within specific ranges, the material achieves both high specific permittivity and improved temperature stability of capacitance.
2Productivity
If liquid phase method is used to manufacture barium titanate, then production efficiency is improved, but residual hydroxyl groups generate holes causing poor electric property
Solution Approach 1:
The patent removes the harmful residual hydroxyl groups (OH groups) that are generated during liquid phase synthesis by applying heat treatment. This extraction of the harmful component eliminates the source of holes in particles, thereby improving the electric properties while maintaining the production efficiency benefits of liquid phase methods.
Solution Approach 2:
The patent converts the harmful effect of residual hydroxyl groups into a beneficial process by using controlled heat treatment to remove them. The heat treatment process, while necessary to eliminate the harmful OH groups and improve electric properties, also serves to enhance the crystallinity and overall quality of the dielectric ceramic material.
3Reliability
If solid phase method is used to manufacture dielectric particles, then particle quality is improved, but crystallinity does not become sufficiently high
Solution Approach 1:
The patent applies preliminary heat treatment to the dielectric particles obtained by solid phase method before final sintering. This preliminary action of heat treatment pre-enhances the crystallinity and removes residual hydroxyl groups, so that when the material undergoes final sintering, it achieves sufficiently high crystallinity and excellent dielectric characteristics.
Solution Approach 2:
The patent combines solid phase method-produced particles with specific oxide additives (Y2O3, MgO, V2O5) and silicate compounds that act as sintering aids. These composite materials facilitate better densification and crystallinity development during sintering, overcoming the limitation of insufficient crystallinity in solid phase method products.
4Volume of moving object
If dielectric ceramic composition is downsized for electronic circuit miniaturization, then electronic component size is reduced, but maintaining good temperature characteristic and capacitance becomes difficult
Solution Approach 1:
The patent uses a composite dielectric ceramic system with BaTiO3 as the main component and multiple oxide additives (Y2O3, MgO, V2O5, MnO, Cr2O3, Co2O3) along with silicate compounds. This composite structure maintains high specific permittivity and stable temperature characteristics even in downsized capacitors, enabling miniaturization without sacrificing performance.
Solution Approach 2:
The patent optimizes compositional parameters within specific ranges (BaTiO3: 86.32 to 97.64 mol%, Y2O3: 0.01 to 10.00 mol%, MgO: 0.01 to 10.00 mol%, etc.) to achieve both high specific permittivity and stable temperature characteristics. These optimized parameters enable the dielectric ceramic to maintain good electrical properties in downsized electronic components.
Data Source
AI summary
A purpose of the present invention is to provide a dielectric ceramic composition which is available to obtain a multilayer ceramic capacitor having a high specific permittivity and a small temperature change of capacitance. A dielectric ceramic composition comprises a dielectric main component composed of 86.32 to 97.64 mol % of BaTiO3, 0.01 to 10.00 mol % of Y2O3 and 0.01 to 10.00 mol % of MgO and 0.001 to 0.200 mol % of V2O5, 0.01 to 1.0 mol % of more than one kind of a first additive selected from a group composed of MnO, Cr2O3, Co2O3, 0.5 to 10.0 mol % of a second additive which is {Baα, Ca (1−α)}SiO3 (note, 0≦α≦1), and Sr: 10 to 500 ppm, S: 10 to 50 ppm, Al: 10 to 50 ppm, Fe: 10 to 50 ppm, Zr: 100 to 800 ppm, Y: 10 to 100 ppm, Hf: 10 to 100 ppm to 100 parts by weight of BaTiO3.