Laminated Ceramic Capacitor Vanadium Segmentation
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Solution Overview
Problem
Laminated ceramic capacitors experience degradation in insulation resistance due to the sintering difference between outer and inner layers caused by the addition of vanadium during firing, leading to locally defective insulation and reduced reliability.
Innovation Solution
A laminated ceramic capacitor design where vanadium is added only to the first insulating layers, which are sintered at a slower rate than the second insulating layers, reducing the sintering state difference and suppressing spheroidization of internal electrodes, thereby maintaining insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vanadium is added to the dielectric ceramic layers, then electrical characteristics are improved and item design range is widened, but sintering difference between outer layers and inner layers increases causing spheroidizing of internal electrodes and degradation of insulation resistance
Solution Approach 1:
The patent applies local quality by adding vanadium only to the inner dielectric ceramic layers (first insulating layers) while excluding it from the outer dielectric ceramic layers (second insulating layers). This localized addition allows the inner layers to benefit from vanadium's electrical characteristic improvements while the outer layers maintain uniform sintering behavior, preventing the spheroidizing of internal electrodes at layer boundaries.
Solution Approach 2:
The patent segments the dielectric ceramic structure into two distinct groups: inner layers containing vanadium and outer layers excluding vanadium. This segmentation resolves the contradiction by allowing different chemical compositions in different regions, enabling the inner layers to achieve improved electrical characteristics while the outer layers ensure uniform sintering and prevent electrode deformation.
2Ease of manufacture
If vanadium is added to increase sintering activity, then sintering temperature is reduced and manufacturing is facilitated, but spheroidizing occurs at layer boundaries causing locally defective insulation resistance
Solution Approach 1:
The patent implements local quality by concentrating vanadium addition in the inner dielectric ceramic layers while keeping the outer layers free of vanadium. This allows the inner layers to utilize vanadium's sintering-promoting effects for easier manufacturing, while the outer layers maintain chemical stability and prevent spheroidizing that would compromise insulation resistance.
Solution Approach 2:
The outer dielectric ceramic layers act as an intermediary barrier between the vanadium-containing inner layers and the internal electrodes. These outer layers without vanadium prevent direct interaction between vanadium and the internal electrodes at the boundaries, thereby preventing spheroidizing while still allowing the inner layers to benefit from vanadium's sintering activity.
3Reliability
If uniform vanadium addition is made to all layers, then electrical characteristics are improved throughout, but temperature distribution difference during firing causes unequal sintering states between outer and inner layers
Solution Approach 1:
The patent applies local quality by creating a non-uniform vanadium distribution: inner dielectric ceramic layers contain vanadium for improved electrical characteristics, while outer dielectric ceramic layers exclude vanadium to ensure uniform sintering. This localized differentiation resolves the contradiction between achieving good electrical properties and maintaining compositional stability during firing.
Solution Approach 2:
The patent introduces asymmetry in the chemical composition of the dielectric ceramic layers. Instead of uniform vanadium addition, the structure has asymmetric composition with vanadium present in inner layers but absent from outer layers. This asymmetric design compensates for the symmetric temperature distribution issue during firing, ensuring that outer layers sinter more uniformly despite being exposed to similar thermal 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 effectively suppresses insulation resistance degradation by controlling the sintering process, ensuring consistent sintering states between layers and improving the reliability of the capacitors.
Implementation Method 1
the addition of vanadium makes the ceramics likely to be sintered
Implementation Method 2
the temperatures of the second insulating layers are increased in a relatively quick manner, whereas the temperatures of the first insulating layers are increased in a relatively slow manner
Data Source
AI summary
Provided is a laminated ceramic capacitor which can suppress degradation of the insulation resistance due to the addition of vanadium. Second insulating layers are stacked on both sides in the stacking direction of a first insulating layer group, which has first insulating layers stacked over one another, and internal electrodes are placed on principal surfaces of the first insulating layers. At least one internal electrode is placed between the first and second insulating layers. Both contain, as their main constituent, a perovskite-type compound represented by the formula “ABO3” wherein “A” denotes at least one of Ba, Sr, and Ca, “B” denotes at least one of Ti, Zr, and Hf. V is added to only the first insulating layers.