Perovskite Dielectric Ceramic Composition for High Voltage MLCCs
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Solution Overview
Problem
Multilayer ceramic capacitors exhibit insufficient properties under high electric field intensities, particularly in terms of specific permittivity, insulation resistance, and reliability, when used at high voltages, necessitating improved dielectric ceramic compositions for enhanced performance.
Innovation Solution
A dielectric ceramic composition based on a perovskite type compound with specific molar ratios of Ba, Sr, Ca, Ti, and Zr, combined with rare earth oxides, is used to create a complete solid solution particle with uniform Zr distribution, maintaining good specific permittivity and improving insulation resistance and high-temperature accelerated lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electric field intensity increases to achieve high rated voltage operation, then the operating voltage range is expanded, but the specific permittivity and insulation resistance decrease
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region has a different sub component concentration than the core. The shell contains a maximum value of sub component concentration near the particle boundary and near the boundary between the shell and core, while the core has a lower concentration. This localized variation in composition allows different regions of the particle to perform different functions: the core maintains basic dielectric properties while the shell enhances insulation resistance and stability under high electric field conditions.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the sub component concentration across the particle structure. The concentration gradient is controlled within specific ranges (0.01≤x≤0.5, 0.01≤y≤0.3, 0.01≤(x+y)≤0.6) to optimize the balance between specific permittivity and insulation resistance. By adjusting these compositional parameters in the shell region while maintaining the core composition, the material achieves improved performance under high electric field intensity.
2Ease of manufacture
If conventional dielectric compositions are used to maintain basic properties, then manufacturing simplicity is preserved, but insulation resistance and lifetime under high electric field are insufficient
Solution Approach 1:
The patent employs composite materials by combining a perovskite type compound base with a sub component forming a core-shell structure. The composite consists of a core region with base composition and a shell region with enhanced sub component concentration. This composite structure integrates the advantages of both simple perovskite materials and complex doped materials, achieving high insulation resistance and lifetime under high electric field while maintaining manufacturability through conventional ceramic processing techniques.
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 achieves improved insulation resistance and high-temperature accelerated lifetime, maintaining basic properties under high electric field intensities, leading to enhanced reliability and performance in multilayer ceramic capacitors.
Implementation Method 1
the dielectric particle include a complete solid solution particle in which Zr is solid dissolved to entire dielectric particle
Data Source
AI summary
The object of the present invention is to provide a dielectric ceramic composition having good properties, particularly good IR property and high temperature accelerated lifetime.The dielectric ceramic composition of the present invention has a main component made of a perovskite type compound expressed by a compositional formula of (Ba1-x-ySrxCay)m(Ti1-zZrz)O3 (note that, m, x, y, and z of the above compositional formula all represent molar ratios, and each satisfies 0.9≤m≤1.1, 0≤x≤0.5, 0≤y≤0.3, 0≤(x+y)≤0.6, and 0.03≤z≤0.3), anda first sub component made of an oxide of a rare earth element R (note that, R is at least one selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), whereinthe dielectric ceramic composition includes a dielectric particle and a particle boundary, and the dielectric particle include a complete solid solution particle in which Zr is solid dissolved to the entire dielectric particle,when Za represents a concentration of Zr in the dielectric ceramic composition in case a concentration of Ti atom in the dielectric ceramic composition is deemed to be 100 atom % and when Zb represents an average concentration of Zr in the complete solid solution particle in case a concentration of Ti atom in the complete solid solution particle is deemed to be 100 atom %,0.7<(Zb/Za) is satisfied, anda standard deviation and an average value of the Zb measured satisfies(the standard deviation/the average value)≤0.15.