Dielectric Ceramic Composition for Multilayer Capacitors
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Solution Overview
Problem
Multilayer ceramic capacitors exhibit insufficient characteristics under high electric field intensities, particularly at high voltages, leading to decreased specific permittivity and insulation resistance, which affects their capacity and reliability.
Innovation Solution
A dielectric ceramic composition comprising a perovskite type compound with specific mol ratios, rare earth element oxides, and sintering agents, where the rare earth element is diffused in the main component to form a diffusion phase occupying 95% or more of the dielectric particle, enhancing insulation resistance and high-temperature accelerated lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the electric field intensity is increased for high voltage application, then the voltage rating is improved, 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 portion has a different composition than the core. The shell contains a higher concentration of sub-components (rare earth elements and zirconium) specifically at regions near the particle boundary and the core-shell interface, while the core maintains the base perovskite composition. This localized compositional variation allows the material to maintain high insulation resistance and specific permittivity even under high electric field conditions.
Solution Approach 2:
The patent employs composite materials by combining multiple elements within the perovskite structure. The dielectric composition includes barium, strontium, calcium, titanium, zirconium, and rare earth elements (such as yttrium, europium, terbium, gadolinium, or dysprosium) in specific ratios. This multi-element composite approach creates a material that exhibits both high voltage tolerance and maintained electrical properties under stress.
2Duration of action of stationary object
If the sub component concentration is increased near particle boundaries to improve capacity-temperature characteristic, then the lifetime characteristic is improved, but the IR characteristic under high electric field becomes insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of sub-components in different regions of the dielectric particles. The shell portion contains rare earth elements at 0.01-0.10 atomic ratio and zirconium at 0.05-0.20 atomic ratio, with these parameters optimized to achieve both improved lifetime characteristics and sufficient IR performance under high electric field conditions. The specific parameter ranges are critical for resolving the contradiction between lifetime and IR characteristics.
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 maintains good specific permittivity and improves insulation resistance and high-temperature accelerated lifetime, ensuring reliable performance even under high electric field intensities.
Implementation Method 1
a diffusion phase wherein said first sub component is diffused in said main component
Data Source
AI summary
A dielectric ceramic composition has good characteristics even under the high electric field intensity, and particularly good IR characteristic and the high temperature accelerated lifetime. The dielectric ceramic composition has a main component having a perovskite type compound shown by a compositional formula (Ba1-x-ySrxCay)m(Ti1-zZrz)O3, a first sub component having oxides of a rare earth element R, a second sub component as a sintering agent, wherein the dielectric particles has dielectric particles having high diffusion rate of the rare earth element, preferably of a complete solid solution particle, and when a concentration of Ti atom in the diffusion phase is 100 atom %, then an average concentration of the rare earth element R in the diffusion phase is 5 atom % or more, and an average concentration of Zr in the diffusion phase is 10 atom % or more.