Dielectric Composition With Segregation Phases for Crack-Resistant MLCCs
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Solution Overview
Problem
Multilayer ceramic electronic devices face defects such as cracks due to low fracture toughness of dielectric compositions, particularly during manufacturing processes like barrel polishing, caused by differences in linear expansion coefficients and external stress.
Innovation Solution
A dielectric composition incorporating a perovskite compound and segregation phases with specific elemental ratios and compositions, including Ca, Al, Si, and O, which enhance inter-grain joint strength and prevent crack growth, thereby increasing fracture toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dielectric compositions are used, then manufacturing process is simple, but fracture toughness is low causing cracks during barrel polishing
Solution Approach 1:
The patent employs composite materials by combining a perovskite compound base with multiple segregation phases (Ca-Al-Si-O and Ca-Si-O). This composite structure enhances fracture toughness through the synergistic effects of different phases: the perovskite provides dielectric properties while the segregation phases prevent crack propagation and strengthen inter-grain joints, resolving the contradiction between strength improvement and composition complexity.
Solution Approach 2:
The patent applies local quality by creating specific segregation phases with controlled compositions and distributions. The Ca-Al-Si-O segregation phase with Al/(Al+Si) ratio of 0.55-0.75 and the Ca-Si-O segregation phase with specific (Ca+Sr)/(Zr+Ti) and Si/(Zr+Ti) ratios are locally formed to provide crack resistance and inter-grain strength at critical locations, allowing the material to achieve high fracture toughness without uniformly complicating the entire composition.
2Reliability
If dielectric composition with high fracture toughness is used, then durability against external force improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes by defining specific compositional ranges for the segregation phases (Al/(Al+Si) ratio of 0.55-0.75, (Ca+Sr)/(Zr+Ti) ratio of 1.15-2.00, Si/(Zr+Ti) ratio of 0.10-0.50). These parameter specifications allow manufacturers to achieve high durability through controlled compositional variations rather than requiring extreme precision in all aspects of manufacturing, balancing reliability improvement with manufacturability.
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 dielectric composition significantly improves the durability of multilayer ceramic electronic devices against external forces and impacts, reducing defect rates during manufacturing and usage.
Implementation Method 1
inclusion of the first segregation phase containing the predetermined elements increases inter-dielectric-grain joint strength
Implementation Method 2
difference in linear expansion coefficients of the ceramic layers and internal electrode layers
Data Source
AI summary
A dielectric composition includes a dielectric grain including a perovskite compound and a first segregation phase including at least Ca, Al, Si, and O.