Lead-Free Dielectric Composition for High Voltage Components
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Solution Overview
Problem
There is a demand for electronic components with high specific permittivity, low dielectric loss, high AC breakdown voltage, and good temperature properties, but existing lead-based dielectric compositions pose environmental concerns.
Innovation Solution
A dielectric composition comprising barium titanate, strontium titanate, and bismuth calcium titanate as the main components, with specific mole percentages and inclusion of manganese, iron, chromium, and niobium compounds to achieve high specific permittivity and AC breakdown voltage while minimizing lead content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-based dielectric composition is used, then high specific permittivity and AC breakdown voltage can be achieved, but environmental harm increases
Solution Approach 1:
The patent changes the chemical composition parameters by completely eliminating lead and replacing it with a lead-free system comprising barium titanate, strontium titanate, and bismuth calcium titanate in specific ratios. This parameter change maintains high dielectric performance (specific permittivity ≥1250, AC breakdown voltage ≥4 kV/mm) while removing the harmful environmental factor of lead contamination
Solution Approach 2:
The patent employs a composite dielectric material system combining multiple ceramic phases (barium titanate, strontium titanate, bismuth calcium titanate) with specific subcomponents (manganese, iron, chromium, and niobium compounds). This composite structure achieves the required electrical properties without relying on toxic lead-based compounds, thereby resolving the contradiction between performance and environmental harm
2Object-affected harmful factors
If lead-free dielectric composition is used, then environmental harm is reduced, but specific permittivity and AC breakdown voltage decrease
Solution Approach 1:
The patent optimizes the compositional parameters of the lead-free system by precisely controlling the ratios of barium titanate (64.8-69.3 mol%), strontium titanate (30.2-35.7 mol%), and bismuth calcium titanate (0.5-5 mol%). Additionally, controlled amounts of subcomponents (manganese: 0.02-0.19 wt%, iron: 0.02-0.19 wt%, chromium: 0.02-0.19 wt%, niobium: 0.1-3 wt%) are added to enhance the electrical properties, achieving AC breakdown voltage ≥4 kV/mm without lead
Solution Approach 2:
The patent develops a multi-phase composite ceramic system where barium titanate provides high permittivity, strontium titanate contributes to dielectric stability, and bismuth calcium titanate enhances AC breakdown strength. The addition of transition metal compounds (Mn, Fe, Cr, Nb) as subcomponents further optimizes the electrical properties, enabling the lead-free composite to achieve reliability comparable to or exceeding traditional lead-based materials
3Object-affected harmful factors
If lead-free dielectric composition is used, then environmental harm is reduced, but dielectric loss increases
Solution Approach 1:
The patent carefully controls the compositional parameters to minimize dielectric loss, achieving tan δ ≤0.5% at 1 kHz and tan δ ≤10% at 1 MHz. The precise formulation of the main component and optimized addition of subcomponents (particularly niobium at 0.1-3 wt%) reduce energy loss mechanisms while maintaining the lead-free composition
Solution Approach 2:
The multi-phase composite structure with barium titanate, strontium titanate, and bismuth calcium titanate creates synergistic effects that reduce dielectric loss. The transition metal subcomponents (Mn, Fe, Cr, Nb) serve as dopants that refine the microstructure and reduce defect-related energy loss, enabling the lead-free material to achieve low dielectric loss comparable to traditional lead-based compositions
Data Source
AI summary
A dielectric composition having a high temperature property, good specific permittivity and AC breakdown voltage, and low dielectric loss at normal temperature, even though lead is not substantially used. The dielectric composition includes barium titanate, strontium titanate, and bismuth calcium titanate constituting a main component and a subcomponent. The dielectric composition includes a first subcomponent constituted by at least one selected from a compound including manganese, a compound including iron, and a compound including chromium, and the first sub component is included in a ratio of 0.02 to 0.19 wt % in terms of total of MnCo3, Fe2O3, and Cr2O3 with respect to 100 wt % of the main component, and the dielectric composition includes a second subcomponent which is a compound including niobium, and the second subcomponent is included in a ratio of 0.1 to 3 wt % in terms of Nb2O5 with respect to 100 wt % of the main component.