Multilayer Ceramic Capacitor Composition for Heat and Moisture Reliability
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Solution Overview
Problem
The demand for high-reliability multilayered capacitors with improved high-temperature and moisture resistance characteristics is increasing, particularly for vehicular applications, but the limited availability of barium titanate powder and restricted manufacturing technology pose challenges in meeting these demands.
Innovation Solution
A multilayered capacitor is developed using a dielectric layer formed with barium titanate as the main component and Dy2O3 as a subcomponent, with controlled Cl content, which enhances crystallinity and reliability, and a method involving the preparation of dielectric powder by wet-mixing barium and titanium precursors, calcining, and forming a conductive paste layer to create a capacitor body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barium titanate powder is used as the main dielectric material, then the capacitor achieves good dielectric properties, but the limited number of suppliers and restricted manufacturing technology reduce reliability and availability
Solution Approach 1:
The patent changes the chemical composition parameters of the barium titanate by controlling the Cl content within specific ranges (0.003-0.03 wt% from BaCO3 and 0.006-0.018 wt% from TiO2) and adjusting the calcination temperature (900-1000°C) and atmosphere (5-15% H2 in N2), thereby optimizing the dielectric properties and crystallinity to improve reliability
Solution Approach 2:
The patent uses a composite dielectric material system where barium titanate is formed from a mixture of BaCO3 and TiO2 precursors with controlled impurity contents, and further composite the dielectric layer with internal electrodes containing Ni, Pd, and Ag in specific ratios to achieve both manufacturing flexibility and enhanced reliability
2Reliability
If the capacitor is designed for high-temperature and moisture resistance, then vehicular application reliability improves, but the manufacturing complexity increases
Solution Approach 1:
The patent optimizes multiple process parameters simultaneously: calcination temperature (900-1000°C), hydrogen concentration in calcination atmosphere (5-15%), and specific Cl content ranges in raw materials, to achieve dielectric crystal grains with high crystallinity that inherently provide high-temperature and moisture resistance without complex additional processing steps
Solution Approach 2:
The patent applies local quality control by specifically managing the Cl content distribution in the barium titanate crystal structure through controlled raw material selection and calcination conditions, creating localized high-quality dielectric regions that enhance overall reliability under harsh conditions
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 provides a multilayered capacitor with improved reliability and withstand voltage characteristics, addressing the limitations of existing technologies by enhancing crystallinity and performance under high-temperature and moisture conditions.
Implementation Method 1
forming dielectric crystal grains of high crystallinity
Implementation Method 2
firing the dielectric green sheet stack to manufacture a capacitor body
Data Source
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AI summary
Disclosed is a multilayered capacitor including a capacitor body including a dielectric layer and an internal electrode and an external electrode disposed outside the capacitor body. The dielectric layer includes a plurality of dielectric crystal grains, the dielectric crystal grains include barium titanate as a main component and Dy2O3 as a subcomponent, and the barium titanate includes about 0.005 to about 0.065 wt% of Cl.