BaTiO3 Core-Shell Ceramic Green Sheet for Insulation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors with core-shell dielectric structures face insulation resistance degradation under high temperature and high electric field due to inhomogeneous solid solutions and concentrated electric fields at grain boundaries, especially when the additive components are not uniformly distributed.
Innovation Solution
A ceramic green sheet with a Si-containing constituent covering 95% or higher and a rare-earth element-containing constituent covering 85% or higher of the barium titanate-based ceramic particle surface, ensuring that rare-earth elements are present at 98% or higher of all grain boundaries in the dielectric layers, reducing the proportion of grain boundaries without additives and suppressing electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a core-shell structure dielectric ceramic is used to increase relative permittivity, then capacitance increases, but insulation resistance degrades under high electric field due to inhomogeneous additive distribution at grain boundaries
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the shell region contains a solid solution of additive components (Sr, Pb, La, Mn, Mg) in BaTiO3, while the core region contains pure or different composition BaTiO3. This localized differentiation ensures that grain boundaries are enriched with additive components that suppress electric field concentration, while the core maintains high permittivity, thus resolving the contradiction between high capacitance and insulation resistance.
Solution Approach 2:
The patent uses composite materials by combining BaTiO3 base ceramic with multiple additive components (SrTiO3, Pb(Zr,Ti)O3, La-doped BaTiO3, Mn-doped BaTiO3, Mg-doped BaTiO3) to form a core-shell structure. This composite approach allows the shell to provide insulation resistance enhancement through additive-rich grain boundaries while the core provides high permittivity, simultaneously achieving both high capacitance and high insulation resistance.
2Quantity of substance
If dielectric layers are made thinner to increase capacitance, then effective area increases, but electric field intensity increases causing accelerated insulation resistance degradation
Solution Approach 1:
The patent applies local quality by concentrating additive components specifically at grain boundaries through the core-shell structure, where the shell region contains solid solutions of Sr, Pb, La, Mn, and Mg in BaTiO3. This localized enrichment at grain boundaries creates regions of lower electric field intensity precisely where field concentration occurs, allowing thin dielectric layers to maintain high insulation resistance despite high overall electric field intensity.
Solution Approach 2:
The patent uses the shell region with additive-containing solid solution as an intermediary between the high-permittivity core and the electrode interfaces. This intermediary shell with enriched additive components acts as a buffer that redistributes and reduces electric field concentration at grain boundaries, enabling thin dielectric layers to withstand high electric fields without insulation resistance degradation.
3Reliability
If additive component concentration is increased to ensure grain boundary coverage, then manufacturing complexity increases, but insulation resistance improves
Solution Approach 1:
The patent applies preliminary action by pre-forming the core-shell structure with additive-enriched shells during the ceramic particle synthesis stage, before sintering. The shell region is prepared with solid solutions of Sr, Pb, La, Mn, and Mg in BaTiO3, ensuring that grain boundaries will be pre-equipped with additive components during sintering. This preliminary preparation eliminates the need for complex post-processing to achieve uniform additive distribution, reducing manufacturing complexity while ensuring high insulation resistance.
Solution Approach 2:
The patent uses parameter changes by controlling the composition ratios of multiple additive components (Sr: 0.01-0.10, Pb: 0.01-0.10, La: 0.01-0.05, Mn: 0.01-0.05, Mg: 0.01-0.05) in the shell region of the core-shell structure. By optimizing these compositional parameters, the patent achieves uniform additive distribution at grain boundaries that ensures high insulation resistance while maintaining manufacturability through standard ceramic processing techniques.
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 approach effectively reduces the proportion of grain boundaries without additive components, thereby suppressing insulation resistance degradation even under high electric fields, leading to a highly reliable multilayer ceramic capacitor with improved high-temperature and high-electric-field performance.
Implementation Method 1
a Si-containing constituent covers 95% or higher of a surface of the barium titanate-based ceramic particle, and a rare-earth element-containing constituent covers 85% or higher of the surface
Implementation Method 2
a solid solution of additive elements in BaTiO3 as a main raw material is believed to be achieved by turning into a liquid phase with, as a starting point, glass containing SiO2 as its main constituent, and incorporating Y, Mn, Mg added to the liquid phase
Implementation Method 3
a solid solution of additive elements in BaTiO3 as a main raw material is believed to be achieved by turning into a liquid phase with, as a starting point, glass containing SiO2 as its main constituent
Data Source
AI summary
A ceramic green sheet where the proportion of a Si-containing constituent coating the surface of barium titanate-based ceramic particles is 95% or higher, and the proportion of a rare-earth element-containing constituent coating the surface of the barium titanate-based ceramic particle is 85% or higher.