Tungsten Bronze Dielectric Composition for High-Temperature Stability
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Solution Overview
Problem
Existing dielectric compositions for laminated ceramic capacitors used in high-temperature automotive applications do not maintain sufficient resistivity and stability across a wide temperature range, particularly from room temperature to 200° C. to 250° C., which is crucial for SiC-based or GaN-based semiconductor power devices.
Innovation Solution
A dielectric composition comprising a tungsten bronze type complex oxide expressed by the chemical formula (K1-xNax)Sr2Nb5O15, with secondary phases such as MgO.SiO2, BaO.2MgO.2SiO2, and 2MgO.B2O3, and accessory components like La2O3, SnO2, Y2O3, Sb2O3, and Nb2O5, which provides high resistivity and low resistivity change ratio across the specified temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dielectric compositions are used, then manufacturing cost is low, but resistivity and insulation properties deteriorate at high temperatures (200°C to 250°C)
Solution Approach 1:
The patent modifies the chemical composition parameters of the dielectric material by incorporating specific metal oxides (Bi2O3 in 0.1-5.0 wt%, ZnO in 0.1-5.0 wt%, B2O3 in 0.1-5.0 wt%) into the tungsten bronze base composition. This parameter adjustment enables the material to maintain high resistivity and insulation properties across the extended temperature range from room temperature to 250°C, directly resolving the contradiction between temperature stability and resistivity maintenance.
Solution Approach 2:
The patent creates a composite dielectric material by combining tungsten bronze type complex oxide with multiple accessory components (Bi2O3, ZnO, B2O3, and other metal oxides). This composite structure leverages the synergistic effects of different materials to achieve both high resistivity at elevated temperatures and stability across the wide temperature range, while maintaining compatibility with existing manufacturing processes.
2Reliability
If accessory components are added to improve high temperature resistivity, then insulation property improves, but manufacturing complexity increases
Solution Approach 1:
The patent establishes specific concentration ranges for each accessory component (Bi2O3: 0.1-5.0 wt%, ZnO: 0.1-5.0 wt%, B2O3: 0.1-5.0 wt%) to optimize insulation performance while controlling manufacturing complexity. By defining precise parameter windows, the patent enables systematic formulation approaches that balance performance improvement with manufacturing feasibility, avoiding excessive complexity.
3Stability of the object's composition
If dielectric composition is optimized for high temperature performance, then resistivity stability improves, but adaptability to different applications decreases
Solution Approach 1:
The patent develops a universal dielectric composition formula based on tungsten bronze type complex oxide that can be adapted to multiple applications including automotive electronics, power devices, and general-purpose capacitors. The composition maintains resistivity change ratio within ±20% from room temperature to 250°C across different applications, achieving both stability and versatility through flexible parameter adjustment within the defined ranges.
Data Source
AI summary
A dielectric composition is provided. The dielectric composition includes a tungsten bronze type complex oxide expressed by a chemical formula (K1-xNax)Sr2Nb5O15 as a main component, x satisfying 0≤x≤0.50, wherein the dielectric composition includes a secondary phase of at least one or more selected from: MgO.SiO2; BaO.2MgO.2SiO2; and 2MgO.B2O3; or the dielectric composition includes a tungsten bronze type complex oxide expressed by a chemical formula (K1-xNax)Sr2Nb5O15 as a main component, x satisfying 0≤x≤0.40, wherein the dielectric composition includes: MgO; BaO; B2O3; SiO2; and P2O5 as a first accessory component in a total content of 2.5 mol to 20.0 mol per 100 mol of the main component.