Dielectric Ceramic Composition with Core-Shell Structure for Capacitor Stability
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Solution Overview
Problem
Existing dielectric ceramic compositions face challenges in simultaneously achieving excellent temperature characteristics and insulation characteristics, as optimizing one often impairs the other.
Innovation Solution
A dielectric ceramic composition with a specific intragranular structure, represented by the formula (Ba1-x-ySrxCay)m(Ti1-zZrz)O3, where m, x, y, and z are molar ratios within certain ranges, and containing specific structural particles with distinct Ca concentrations, enhancing both temperature stability and insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the composition ratio of paraelectric material is optimized to improve temperature characteristics, then temperature coefficient of capacitance is reduced, but insulation resistance deteriorates
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the particle center (core) has low Ca concentration for maintaining insulation resistance, while the outer region (shell) has high Ca concentration for improving temperature characteristics. This spatial differentiation of composition allows simultaneous optimization of both insulation and temperature stability properties that cannot be achieved with uniform composition.
Solution Approach 2:
The invention segments the dielectric particle into two distinct regions: a first region (core) with low Ca concentration and a second region (shell) with high Ca concentration. This segmentation enables each region to contribute differently to the overall performance - the core maintains insulation properties while the shell provides temperature stability, resolving the contradiction between these two characteristics.
2Stability of the object's composition
If Ca concentration is increased to improve temperature characteristics, then temperature coefficient of capacitance is reduced, but insulation resistance decreases
Solution Approach 1:
By applying local quality, the invention places high Ca concentration specifically in the outer region of the particle where it contributes to temperature stability without compromising the insulation properties maintained in the low Ca concentration core region. This localized composition strategy allows high Ca content (good for temperature characteristics) without the penalty of reduced insulation resistance that would occur with uniform high Ca distribution.
Solution Approach 2:
The segmentation of Ca concentration into core and shell regions enables the outer shell to bear the burden of temperature stabilization through high Ca content, while the core preserves insulation resistance through low Ca content. This functional segmentation resolves the contradiction by assigning different compositional requirements to different spatial zones within the particle.
Data Source
AI summary
A dielectric ceramic composition contains dielectric particles containing a main component represented by a composition formula (Ba1-x-ySrxCay)m(Ti1-zZrz)O3 and grain boundaries present between the dielectric particles. The values of m, x, y, and z in the composition formula are all molar ratios. In the composition formula, 0.9≤m≤1.4, 0≤x<1.0, 0<y≤1.0, 0.9≤(x+y)≤1.0, and 0.9≤z≤1.0 are satisfied. The dielectric particles contain specific structural particles having a predetermined intragranular structure, and each of the specific structural particles intragranularly includes a first region and a second region having different Ca concentrations from each other. C2/C1 is less than 0.8 in which C1 is an average value of the Ca concentration in the first region and C2 is an average value of the Ca concentration in the second region.