Dielectric Ceramic Composition for Thin-Layer Capacitor Reliability
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Solution Overview
Problem
Dielectric ceramic layers in laminated ceramic capacitors become unreliable as they thin, leading to insufficient lifetime characteristics in load tests, despite efforts to improve electric properties with rare-earth elements and Mn additions.
Innovation Solution
A dielectric ceramic composition of (Ba,R)(Ti,Mn)O3 or (Ba,Ca,R)(Ti,Mn)O3 with M and Si as accessory components, where Mn and R are present as solid solutions in the main component grains, limiting the M component's area to 10% or less, enhancing insulating properties and suppressing local grain growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dielectric ceramic layers are reduced in thickness to achieve size reduction and higher capacity, then the capacitor capacity increases and size decreases, but the electric field intensity increases and reliability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region contains M components (Fe, Co, V, W, Cr, Mo, Cu, Al, or Mg) distributed only in the shell portion而非均匀分布。这种局部成分优化使得陶瓷层在保持薄厚度的同时，通过壳层中的M成分抑制局部分解和晶粒过度生长，提高了击穿电压和可靠性
Solution Approach 2:
The patent uses composite materials by combining BaTiO3-based dielectric ceramic with rare-earth elements (R) and M components to form a multi-component system. The specific composition (Ba,R)(Ti,Mn)O3 or (Ba,Ca,R)(Ti,Mn)O3 with controlled M content (10% or less area ratio in shell) creates a composite structure that simultaneously achieves high capacity and high reliability in thin layers
2Reliability
If rare-earth elements and Mn are added to improve electric properties, then the dielectric properties improve, but the complexity of composition increases and manufacturing difficulty increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition parameters: R content (0.01-2 mol%), Mn content (0.01-1 mol%), and M content (area ratio 10% or less in shell). These parameter optimizations enable the ceramic to achieve high breakdown voltage while maintaining manufacturability through defined compositional ranges
Solution Approach 2:
The patent reduces manufacturing complexity by localizing M components to the shell region with specific area ratios, rather than requiring uniform distribution throughout the entire grain. This localized approach simplifies the sintering process control compared to achieving homogeneous distribution of multiple elements
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
This composition ensures high reliability and favorable lifetime characteristics in thin laminated ceramic capacitors by improving insulating properties and preventing local grain growth, maintaining performance in load tests.
Implementation Method 1
Mn is present homogeneously as a solid solution in the main component grains, thereby improving the insulating property in the main component grains. In addition, R is also present homogeneously as a solid solution in the main component grains, thereby improving the insulating property in the main component grains.
Implementation Method 2
The solid solution region with the M component as an accessory component therein is 10% or less, and local grain growth can be thus suppressed on firing.
Data Source
AI summary
A dielectric ceramic which is capable of achieving a laminated ceramic capacitor with high reliability, in particular, favorable lifetime characteristics in a load test, even when a dielectric ceramic layer is reduced in thickness contains one of (Ba,R)(Ti,Mn)O3 and (Ba,Ca,R)(Ti,Mn)O3 (R being La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or Y) as a main component, and M (M being Fe, Co, V, W, Cr, Mo, Cu, Al, and/or Mg) and Si as accessory components. The area of a region in which M is present is 10% or less on average of a cross section of each main component grain.