Lead-Free Dielectric Composition for High-Permittivity Capacitors
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Solution Overview
Problem
There is a demand for compact electronic components with high performance and low dielectric loss, high DC breakdown voltage, and good temperature properties, while avoiding the use of lead due to environmental concerns.
Innovation Solution
A dielectric composition comprising barium titanate, strontium titanate, and bismuth calcium titanate as main components, with specific content ranges and inclusion of manganese, iron, chromium, and niobium compounds as subcomponents, which together achieve high permittivity, low dielectric loss, and high DC breakdown voltage without using lead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-containing dielectric composition (PbTiO3—SrTiO3—Bi2Ti3O9) is used to achieve high permittivity and high DC breakdown voltage, then the dielectric performance is improved, but environmental harm increases due to lead content
Solution Approach 1:
The patent changes the chemical composition parameters by replacing lead (Pb) with barium (Ba) as the primary cation, while adjusting the ratios of SrTiO3 and CaBi4Ti4O15 to maintain high permittivity and DC breakdown voltage. This parameter substitution achieves environmental compliance while preserving dielectric performance
Solution Approach 2:
The patent creates a composite dielectric material system consisting of BaTiO3, SrTiO3, and CaBi4Ti4O15 in specific proportions. This composite approach combines the high permittivity of BaTiO3 with the stability and breakdown voltage characteristics of SrTiO3 and CaBi4Ti4O15, achieving lead-free high-performance dielectric properties
2Volume of moving object
If the dielectric composition is made compact to reduce device size, then the electronic component becomes more compact, but maintaining good temperature property and low dielectric loss becomes more difficult
Solution Approach 1:
The patent optimizes the compositional parameters within specific ranges (50≤a≤83, 12≤b≤49.5, 0.5≤c≤5) to achieve a balance between compactness and performance. The precise control of BaTiO3, SrTiO3, and CaBi4Ti4O15 ratios enables compact device design while maintaining temperature stability and low dielectric loss
Solution Approach 2:
The patent introduces subcomponents with specific elements (Mn, Fe, Cr, Nb) at controlled concentrations to locally enhance specific properties. These dopants are strategically added to improve temperature compensation and reduce dielectric loss in the compact structure without compromising overall performance
3Reliability
If higher permittivity is achieved to maintain capacitance in compact designs, then capacitance is maintained, but dielectric loss and heat generation increase
Solution Approach 1:
The patent carefully adjusts the compositional parameters to achieve high permittivity through the BaTiO3-based system while controlling dielectric loss. The specific ratio ranges and subcomponent additions are optimized to maximize permittivity while minimizing energy loss and heat generation
Solution Approach 2:
The patent uses targeted doping with specific elements (Nb, Mn, Fe, Cr) at controlled concentrations to locally improve dielectric properties. These subcomponents are added to reduce dielectric loss and improve temperature stability without significantly increasing heat generation, achieving a balance between high permittivity and low energy loss
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 composition attains high specific permittivity, low dielectric loss, and excellent heat generating properties, along with high DC breakdown voltage, and allows for the use of Cu-electrodes, reducing costs and environmental impact.
Implementation Method 1
the dielectric composition includes barium titanate, strontium titanate, and bismuth calcium titanate constituting a main component... high specific permittivity and DC breakdown voltage can be attained
Implementation Method 2
said dielectric composition includes a first subcomponent constituted by at least one selected from the group consisting of a compound including manganese, a compound including iron, and a compound including chromium... a dielectric loss can be made low at normal temperature, and good heat generating property and temperature property can be attained
Implementation Method 3
said dielectric composition includes a second subcomponent which is a compound including niobium... high specific permittivity and DC breakdown voltage can be attained
Data Source
AI summary
A dielectric composition has barium, strontium, and bismuth calcium titanates constituting a main component and subcomponent. “a” mol % represents a content of barium titanate in terms of BaTiO3, “b” mol % strontium titanate in terms of SrTiO3, and “c” mol % bismuth calcium titanate in terms of CaBi4Ti4O15 in the main component composition. a+b+c=100 is satisfied, 50≤a≤83, 12≤b≤49.5, 0.5≤c≤5. The dielectric composition includes a first subcomponent constituted by at least one compound including one of manganese, iron, and chromium. The first subcomponent is included in a ratio of 0.2 wt % or more and 3 wt % or less in terms of total of MnCO3, Fe2O3, and Cr2O3 with respect to 100 wt % of the main component. The dielectric composition includes a second subcomponent compound including niobium, included in a ratio of 0.1 wt % or more and 3 wt % or less in terms of Nb2O5 with respect to 100 wt % of the main component.