Dielectric Ceramic Composition Surface Diffusion Structure X8R
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high temperature accelerated life and X8R characteristics, as existing dielectric ceramic compositions either fail to satisfy the required temperature range or have insufficient insulation resistance and dielectric constant performance.
Innovation Solution
A dielectric ceramic composition with a surface diffusion structure, where barium titanate is the main ingredient and the ratio of dielectric particles with a surface diffusion structure is 60% or more, and those with a domain in the main ingredient phase is 20% or less, improving high temperature load life and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If dielectric particles with core-shell structure are used to improve dielectric constant and temperature characteristic, then dielectric constant improves, but the capacitor only satisfies JIS DJ or BJ characteristic and fails to satisfy X8R characteristic
Solution Approach 1:
The patent applies local quality by creating a surface diffusion structure where only the outer layer of dielectric particles has a specific composition (with diffused Ca ions), while the inner core maintains the original barium titanate composition. This localized structural differentiation enables the capacitor to satisfy X8R characteristic while maintaining good dielectric properties.
2Quantity of substance
If conventional dielectric ceramic composition is used to achieve high dielectric constant, then dielectric constant improves, but high temperature accelerated life and insulation resistance performance become insufficient
Solution Approach 1:
The patent uses composite materials by combining barium titanate particles with a surface diffusion layer containing calcium ions and other oxides. This composite structure at the particle level provides both high dielectric constant from the barium titanate core and improved high temperature accelerated life from the protective surface layer with controlled composition and structure.
3Adaptability or versatility
If dielectric ceramic composition is designed for broad temperature range operation, then temperature range expands, but maintaining flat temperature characteristics becomes more difficult
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple oxides (CaO, SiO2, V2O5, MoO3, WO3, and rare earth oxides) in the surface diffusion layer, and by optimizing the diffusion depth parameter (10-30% of average particle size). These parameter optimizations enable the capacitor to maintain flat temperature characteristics across the broad -55 to 150°C range required for X8R classification.
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 effectively satisfies the X8R characteristic, enhances high temperature accelerated life, and maintains a stable insulation resistance across a broad temperature range, improving the performance of multilayer ceramic capacitors.
Implementation Method 1
dielectric particles having a surface diffusion structure comprised of a main ingredient phase and a diffusion phase
Data Source
Figure 1
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Figure 3(A)~3(B)
AI summary
A dielectric ceramic composition comprised of at least dielectric particles having barium titanate as its main ingredient, wherein the ratio of dielectric particles having a surface diffusion structure comprised of a main ingredient phase comprised of the main ingredient and a diffusion phase present around the main ingredient phase with respect to said dielectric particles is 60% or more and the ratio of dielectric particles having a domain in the main ingredient phase with respect to the dielectric particles having the surface diffusion structure is 20% or less. According to the present invention, a dielectric ceramic composition and electronic device realizing good high temperature accelerated life can be provided.