Multi-Layer Ceramic Capacitor Bonding Unit Magnesium Concentration
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Solution Overview
Problem
Multi-layer ceramic capacitors face challenges in achieving high reliability and capacitance while maintaining sufficient sinterability, as excessive magnesium in the ceramic layers can inhibit grain growth and reduce capacitance, and insufficient sinterability can lead to malfunction or peeling issues.
Innovation Solution
A multi-layer ceramic capacitor design with a bonding unit having a higher magnesium concentration than the ceramic layers and side margins, where magnesium diffuses to form oxidized regions adjacent to internal electrodes, enhancing reliability and preventing short circuits, while maintaining low magnesium levels in the ceramic layers to preserve capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnesium is added in large amounts to the protective section to improve sinterability, then sinterability is improved, but crystal grains become minute and capacitance is lowered
Solution Approach 1:
The patent applies local quality by creating distinct magnesium concentration zones: the bonding unit has high magnesium concentration (0.1-5 mass%) to ensure sinterability and form oxidized regions, while the ceramic layers have low magnesium concentration (0.01-0.1 mass%) to maintain large crystal grains and high capacitance. This spatial differentiation resolves the contradiction between sinterability and capacitance.
Solution Approach 2:
The protective section is segmented into two functional parts: the bonding unit adjacent to internal electrodes that provides magnesium for oxidized region formation, and the side margin that provides magnesium for sinterability. This segmentation allows each part to optimize magnesium concentration for its specific function without compromising the other.
2Reliability
If magnesium concentration is increased in side gap portions to ensure sinterability, then sinterability is improved, but more magnesium diffuses to ceramic layers and capacitance is lowered
Solution Approach 1:
The bonding unit acts as an intermediary that controls magnesium distribution. It has high magnesium concentration to supply magnesium for oxidized region formation, but its strategic placement and concentration gradient prevent excessive magnesium diffusion into the ceramic layers, thus protecting capacitance while ensuring sinterability.
Solution Approach 2:
The patent changes the magnesium concentration parameter spatially: high concentration (0.1-5 mass%) in the bonding unit for sinterability and oxidized region formation, and low concentration (0.01-0.1 mass%) in the ceramic layers for capacitance maintenance. This parameter differentiation resolves the contradiction.
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 ensures high reliability and capacitance without impairing sinterability, as magnesium is accurately supplied to the bonding and side margins, preventing short circuits and maintaining large crystal grains in the ceramic layers.
Implementation Method 1
the magnesium diffuses from the bonding unit to the multi-layer unit at the time of sintering
Implementation Method 2
magnesium has the action of inhibiting grain growth at the time of sintering
Implementation Method 3
the sinterability is prone to be lowered... In order to ensure the sinterability in the protective section, it is effective to provide magnesium in large amounts to the protective section
Implementation Method 4
This allows Ni to generate an oxidized compound together with Mg derived from the side gap portions in the region adjacent to the side surfaces of the internal electrodes
Data Source
AI summary
A multi-layer ceramic capacitor includes a multi-layer unit, a side margin, and a bonding unit. The multi-layer unit includes ceramic layers laminated in a first direction, and internal electrodes disposed between the ceramic layers and mainly containing nickel. The side margin covers the multi-layer unit from a second direction orthogonal to the first direction. The bonding unit is disposed between the multi-layer unit and the side margin and has a higher concentration of magnesium than the ceramic layers and the side margin.