Multilayer Ceramic Capacitor Composition for High-Temperature Stability
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Solution Overview
Problem
Multilayer ceramic capacitors with barium titanate dielectric materials face significant capacitance degradation at temperatures above 150°C, making them unsuitable for high-temperature environments, and they cannot be used reliably above 200°C due to the unique characteristics of barium titanate oxide.
Innovation Solution
A method of manufacturing multilayer ceramic capacitors using a dielectric magnetic composition with base material powder particles of BaTi2O5 or (Ba(1-x)Cax)Ti2O5, where the particles are coated with Mg, Mn, V, Ba, Si, Al, and rare earth metals, which are then used to create ceramic green sheets, internal electrodes, and a ceramic body with dielectric layers, allowing for high-temperature capacitance stability and increased capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barium titanate (BaTiO3) is used as the dielectric material to achieve high capacitance, then the capacitance is significantly decreased in an environment of 150°C or more
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric material from pure barium titanate (BaTiO3) to a modified composition containing BaTi2O5 and CaTiO3 in specific ratios. This compositional parameter change enables the material to maintain high capacitance while achieving stability at temperatures up to 200°C, resolving the contradiction between high capacitance and high-temperature reliability
Solution Approach 2:
The patent creates a composite dielectric material by combining multiple ceramic powders (BaTi2O5, CaTiO3, and other auxiliary oxides) in specific proportions. This composite approach leverages the complementary properties of each component to achieve both high capacitance and high-temperature stability, overcoming the limitations of single-material barium titanate
2Ease of manufacture
If nickel (Ni) internal electrodes are used with barium titanate dielectric material, then the ceramic body needs to be sintered under a reducing atmosphere, but the dielectric material needs to have reduction resistance
Solution Approach 1:
The patent modifies the dielectric material composition to include BaTi2O5 and CaTiO3, which have inherent resistance to reduction. This compositional change allows the material to withstand the reducing atmosphere required for nickel electrode sintering without degrading, thus resolving the contradiction between ease of manufacture and reduction resistance
Solution Approach 2:
The modified dielectric composition acts as an intermediary that mediates between the nickel internal electrodes and the reducing atmosphere. The specific composition (BaTi2O5-CaTiO3 system) provides a buffer that protects the nickel electrodes from excessive oxidation while maintaining the necessary sintering conditions, thus resolving the contradiction between ease of manufacture and reduction resistance
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 solution stabilizes high-temperature capacitance change rates and enhances the dielectric constant, enabling the use of multilayer ceramic capacitors in high-temperature environments, such as those found in internal combustion engine vehicles and electric vehicles, while preventing nickel diffusion into the dielectric layer and maintaining reliability.
Implementation Method 1
enhances the dielectric constant, enabling the use of multilayer ceramic capacitors in high-temperature environments
Implementation Method 2
preventing nickel diffusion into the dielectric layer and maintaining reliability
Data Source
AI summary
A method of manufacturing a multilayer ceramic electronic component includes: preparing a dielectric magnetic composition including base material powder particles including BaTi2O5 or (Ba(1-x)Cax)Ti2O5 (0≤x≤0.1), the base material powder particles having surfaces coated with one or more of Mg, Mn, V, Ba, Si, Al and a rare earth metal; preparing ceramic green sheets using dielectric slurry including the dielectric magnetic composition; applying an internal electrode paste to the ceramic green sheets; preparing a green sheet laminate by stacking the ceramic green sheets to which the internal electrode paste is applied; and preparing a ceramic body including dielectric layers and a plurality of first and second internal electrodes arranged to face each other with each of the dielectric layers interposed therebetween by sintering the green sheet laminate.