Core-Shell Dielectric Ceramics for Stable Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors with core-shell structured dielectric ceramics face challenges in maintaining high insulation resistance and long life under high-temperature durability tests due to voltage dependence, especially when subjected to direct-current voltage increases.
Innovation Solution
Dielectric ceramics with a core-shell structure comprising barium titanate, vanadium, magnesium, and rare-earth elements like yttrium, dysprosium, holmium, or terbium, and manganese, optimized to have a Curie temperature between 80° C. and 90° C., reducing voltage dependence and enhancing insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If core-shell structured dielectric ceramics with barium titanate are used to achieve high dielectric constant, then the relative dielectric constant is improved, but the insulation resistance decreases under direct-current voltage
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of barium titanate (0.95-1.05 mol), bismuth oxide (0.02-0.08 mol), and zinc oxide (0.02-0.08 mol), along with adjusting the Curie temperature to 80-90°C. These parameter optimizations resolve the contradiction by achieving high dielectric constant while maintaining stable insulation resistance under voltage conditions.
Solution Approach 2:
The patent uses composite materials by combining barium titanate with bismuth oxide and zinc oxide to form a multi-component dielectric system. This composite approach enables the material to simultaneously achieve high dielectric constant and improved insulation resistance, resolving the technical contradiction between these two properties.
2Quantity of substance
If core-shell structured dielectric ceramics are used to achieve high dielectric constant, then the relative dielectric constant is improved, but the life in high-temperature durability test decreases
Solution Approach 1:
The patent optimizes parameters by controlling the Curie temperature within 80-90°C and precisely adjusting the molar ratios of barium titanate, bismuth oxide, and zinc oxide. These parameter changes enable the dielectric ceramics to maintain both high dielectric constant and extended operational life under high-temperature durability conditions.
Solution Approach 2:
The patent implements local quality through the core-shell structure where the core region provides high dielectric constant while the shell region, enriched with bismuth oxide and zinc oxide, provides thermal stability and extended life. This spatial differentiation of material properties resolves the contradiction between dielectric performance and durability.
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 optimized dielectric ceramics achieve a high relative dielectric constant with stable temperature dependence and improved insulation resistance, enabling multilayer ceramic capacitors to maintain performance and longevity in high-temperature durability tests.
Implementation Method 1
A dielectric ceramics comprising a high dielectric constant is disclosed. The dielectric ceramics also comprises a relative dielectric constant with a stable temperature dependence
Data Source
AI summary
A dielectric ceramic exhibiting a high dielectric constant is provided. The relative dielectric constant of the dielectric ceramic is stable with respect to temperature dependence and exhibits insulation resistance having a reduced voltage dependence. The dielectric ceramic of the invention can be used to form a multilayer ceramic capacitor that has a long life.