Dielectric Ceramic Composition for High-Temperature Stability
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Solution Overview
Problem
Current dielectric ceramic compositions with tungsten bronze structures lack high dielectric constants and stability in high-temperature environments, especially when fired in a reducing atmosphere, and do not exhibit low dielectric losses across a wide temperature range.
Innovation Solution
A dielectric ceramic composition comprising specific oxides such as Ca, Sr, Ba, Ti, Zr, Sn, Nb, Ta, and V, with Mn as a secondary component, formulated to maintain high dielectric constants and low dielectric losses even at elevated temperatures, allowing for firing in a reducing atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barium titanate is used for the dielectric layer, then the dielectric constant is high, but the dielectric constant has a peak at ferroelectric transition temperature and properties rapidly decline when temperature reaches 120°C or higher
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating multiple metal elements (Ca, Sr, Ba, Ti, Zr, Sn, Nb, Ta, V) in specific ratios to modify the dielectric properties. This compositional adjustment shifts the phase transition behavior and broadens the stable temperature range, allowing high dielectric constant to be maintained at temperatures above 120°C without the sharp peak characteristic of pure barium titanate.
Solution Approach 2:
The invention uses a composite ceramic material combining multiple oxide components rather than a single compound. This multi-element composite approach (containing at least three of Ca, Sr, Ba and at least two of Ti, Zr, Sn along with Nb, Ta, V) creates synergistic effects that simultaneously achieve high dielectric constant and improved high-temperature stability, overcoming the limitations of individual materials.
2Ease of manufacture
If a base metal such as nickel or copper is used as the internal electrode material, then the dielectric layer and internal electrode can be co-fired in a reducing atmosphere, but the dielectric ceramic composition requires specific additive components to maintain stability
Solution Approach 1:
The patent adjusts the chemical composition parameters of the dielectric ceramic to include specific additive components (Nb, Ta, V oxides) that stabilize the material during reducing atmosphere firing. These compositional modifications enable the ceramic to withstand the reducing conditions without degradation, while maintaining its dielectric properties and structural integrity throughout the co-firing process with base metal electrodes.
Data Source
AI summary
According to the present invention, a dielectric ceramic composition, which can be fired in a reducing atmosphere, has a high dielectric constant, has an electrostatic capacity exhibiting little change, when used as a dielectric layer of a ceramic electronic component such as a laminated ceramic capacitor even under a condition of 150 to 200° C., and has small dielectric losses at 25° C. and 200° C., can be provided.