Multilayer Ceramic Capacitor Grain Boundary Control
Solution Overview
Problem
Multilayer ceramic capacitors produced using tunnel type large-scale sintering furnaces face challenges in maintaining high relative permittivity, temperature stability, and accelerated life test properties due to significant temperature fluctuations, leading to decreased yield in mass production.
Innovation Solution
Incorporating a dielectric layer with crystal particles and grain boundary phases, where the Si—Ba—O compound forms in 5% or more of the triple point grain boundaries per unit surface area, along with a specific composition of barium titanate powders and additives, to control grain growth and enhance ferroelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If tunnel type large-scale sintering furnace is used for mass production, then productivity is improved, but manufacturing precision deteriorates due to significant temperature fluctuations
Solution Approach 1:
The patent applies local quality by forming Si-Ba-O compounds specifically at triple point grain boundaries (where three crystal particles meet) rather than uniformly throughout the material. This localized formation at 5% or more of triple point grain boundaries compensates for temperature fluctuations by creating stable regions that maintain consistent grain growth and dielectric properties across different sintering conditions, thereby enabling mass production while maintaining manufacturing precision.
2Manufacturing precision
If sintering temperature is precisely controlled, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent changes the chemical parameter by introducing glass components that form Si-Ba-O compounds at grain boundaries. This chemical modification alters the sintering behavior and grain growth characteristics, making the material less sensitive to temperature fluctuations. As a result, mass production can proceed with standard temperature control while maintaining consistent product quality.
3Reliability
If glass component is added to dielectric material, then relative permittivity is improved, but grain growth control becomes difficult
Solution Approach 1:
The patent uses Si-Ba-O compounds formed from glass components as intermediaries at grain boundaries. These compounds act as barriers that regulate grain growth while maintaining high relative permittivity. The Si-Ba-O compounds at triple point grain boundaries specifically control the growth of BCT crystal particles, preventing excessive grain growth while preserving the dielectric properties enhanced by glass addition.
4Reliability
If BCT powder with Ca substitution is used, then relative permittivity is improved, but grain growth is accelerated
Solution Approach 1:
The patent converts the harmful effect of accelerated grain growth into a beneficial outcome by utilizing the glass components to form Si-Ba-O compounds at grain boundaries. These compounds selectively inhibit further grain growth of BCT particles that have already grown to optimal sizes, thereby converting the initial grain growth acceleration into a controlled process that achieves both high relative permittivity and fine-grained microstructure.
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 configuration stabilizes the relative permittivity, temperature properties, and highly accelerated life test performance, even in mass production, by locally distributing glass components and additives, thereby improving the insulation and ferroelectric properties of the capacitor.
Implementation Method 1
Si—Ba—O compound is formed in 5% or more of the triple point grain boundaries
Implementation Method 2
a dielectric layer which comprises a plurality of crystal particles and grain boundary phases
Implementation Method 3
locally distributing glass components and additives, thereby improving the insulation and ferroelectric properties
Data Source
AI summary
The invention provides a multilayer ceramic capacitor comprising a capacitor body composed by alternately layering dielectric layers and inner electrode layers. Accordingly, the multilayer ceramic capacitor has high relative permittivity and is high the temperature property and highly accelerated life test property.