MLCC Boron Gradient Side Margin Suppresses Over-Sintering
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Solution Overview
Problem
Multi-layer ceramic capacitors face issues with over-sintering, leading to short circuits and reduced insulation resistance due to the spheroidization or segmentation of internal electrodes, especially when boron is added to promote densification, as it can cause excessive grain growth and reduce capacitance.
Innovation Solution
A multi-layer ceramic electronic component configuration with a capacitance forming unit containing boron-doped ceramic layers and a side margin with a lower boron concentration, where the boron concentration gradually decreases from the center to the side margin, inhibiting over-sintering and promoting densification, thereby reducing the occurrence of short circuits and enhancing capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If boron is added to the ceramic layer to promote densification, then sintering temperature is lowered and densification is improved, but the internal electrodes are easily spheroidized or segmented causing over-sintering
Solution Approach 1:
The patent applies local quality by creating a boron concentration gradient within the ceramic body. The ceramic layers contain a first boron concentration to promote densification, while the side margins contain a lower boron concentration to suppress over-sintering. This spatial variation in boron concentration allows different regions to have different sintering characteristics, resolving the contradiction between achieving densification and preventing electrode degradation.
2Quantity of substance
If side margins are thinned to ensure large intersectional area of internal electrodes, then capacitance is increased, but insulation properties of the periphery may be compromised
Solution Approach 1:
The patent resolves this contradiction by applying local quality through differentiated boron concentration zones. The side margins have reduced boron concentration specifically to prevent over-sintering in these peripheral regions, thereby maintaining insulation properties even when side margins are thinned to maximize the internal electrode intersectional area and capacitance.
Solution Approach 2:
The patent effectively creates a composite ceramic structure with two distinct material compositions: ceramic layers with higher boron concentration for densification and side margins with lower boron concentration for insulation. This composite approach allows simultaneous optimization of both capacitance (through thinned side margins) and insulation properties (through boron-depleted marginal zones).
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
This configuration effectively suppresses over-sintering, reduces short circuit failures, and maintains high insulation resistance by controlling boron concentration gradients, allowing for sintering at lower temperatures and achieving larger capacitance values.
Implementation Method 1
at the sintering of a ceramic body, a ceramic layer disposed at a portion close to the surface of the ceramic body, i.e., a superficial portion, is likely to be over-sintered
Implementation Method 2
adding boron (B) to the ceramic layer provides an effect of promoting densification of a ceramic layer
Implementation Method 3
The side margin covers the side surface in the second direction and has a lower boron concentration than a boron concentration of the ceramic layers... it is possible to inhibit the vicinity of the end portions of the internal electrodes in the second direction from being spheroidized or segmented by over-sintering
Data Source
AI summary
A multi-layer ceramic electronic component includes a multi-layer unit and a side margin. The multi-layer unit includes a capacitance forming unit, a cover, and a side surface. The capacitance forming unit includes ceramic layers that are laminated in a first direction and contain boron, and internal electrodes disposed between the ceramic layers. The cover covers the capacitance forming unit in the first direction. The side surface faces in a second direction orthogonal to the first direction. The side margin covers the side surface in the second direction and has a lower boron concentration than a boron concentration of the ceramic layers.