Dielectric Ceramic Composition for Low-Temperature Firing
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Solution Overview
Problem
Existing dielectric porcelain compositions for stack ceramic capacitors have a dielectric constant less than 1500, making it difficult to meet demands for smaller scale and larger capacity, and require higher temperature firing due to reduced internal electrode thickness and the need for low-temperature sintering.
Innovation Solution
A dielectric ceramic composition comprising (Ba1-x-yCaxSry)m(Ti1-zZrz)O3 with Bi and optionally Cu, where Bi content is 1.0 to 40 parts by mol and Cu content is 0.1 to 1 part by mol, allowing for low-temperature firing and improved dielectric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If internal electrode thickness is reduced to enable further scale reduction, then the covering ratio of internal electrodes decreases due to spherical metal grains, but this requires firing at lower temperatures which conflicts with the need to maintain dielectric characteristics
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic by incorporating specific amounts of Bi2O3 (1-40 mol%) and CuO (0.1-1 mol%) to modify the firing behavior and metal grain morphology, enabling lower temperature firing while maintaining adequate covering ratio
Solution Approach 2:
The patent creates a composite dielectric system combining Ba1-x-yCaxSry(Ti1-zZrz)O3 with Bi2O3 and CuO additives, where the composite composition works synergistically to achieve both low-temperature firing and maintained dielectric characteristics with improved metal grain structure
2Temperature
If firing temperature is reduced to accommodate thinner internal electrodes, then low-temperature firing becomes possible, but the dielectric constant remains insufficient (less than 1500) in existing compositions
Solution Approach 1:
The patent optimizes the compositional parameters including the m ratio (1.005-1.2) of Ba1-x-yCaxSry(Ti1-zZrz)O3 and controlled amounts of Bi2O3 and CuO to achieve a composition that forms a dense microstructure and high dielectric constant at reduced firing temperatures of 900-1100°C
Solution Approach 2:
The patent introduces localized Bi2O3 and CuO phases within the dielectric matrix that create liquid phase sintering regions, improving densification and dielectric properties at lower temperatures without compromising the overall dielectric constant
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 dielectric ceramic enables low-temperature firing while maintaining high dielectric constants and low dielectric loss, facilitating the production of smaller, higher-performance stack ceramic electronic components.
Implementation Method 1
a ceramic material capable of being fired at a low temperature and exhibiting excellent dielectric characteristics is demanded
Data Source
AI summary
A dielectric ceramic enabling low-temperature firing and exhibiting good dielectric characteristics, and a stack ceramic electronic component using the same are provided. The dielectric ceramic containing (Ba1-x-yCaxSry)m(Ti1-zZrz)O3 (1.005≦m≦1.2, 0≦x+y≦0.2, and 0≦z≦0.2) as a major component and an amount of Bi relative to 100 parts by mol of the major component which is 1.0 part by mol or more and 40 parts by mol or less.