Laminated Ceramic Capacitor Columnar Members Stress Relaxation
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Solution Overview
Problem
Laminated ceramic electronic components, such as capacitors, face issues with delamination and cracking due to differences in sintering shrinkage and thermal expansion between ceramic layers and internal electrodes, which are exacerbated by increased layer numbers and reduced thickness, leading to potential performance decreases.
Innovation Solution
The formation of non-penetrating ceramic columnar members within the internal electrodes, with base ends at the interface and tips within the electrodes, helps to relax thermal stress and reinforce joints, preventing delamination and cracking while allowing for reduced layer thickness and increased layer numbers without breaking the internal electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of internal electrodes is increased to enhance capacitance, then electrostatic capacitance increases, but internal stress and thermal stress increase causing cracks and delamination
Solution Approach 1:
A glass phase is introduced as an intermediary substance at the interface between the internal electrode and ceramic layer. This glass phase acts as a stress-relief mediator that reduces internal stress and thermal stress, preventing cracks and delamination while allowing increased number of internal electrodes for higher capacitance
Solution Approach 2:
The internal electrode structure is modified to include a composite configuration with a glass phase layer at the interface between the metal internal electrode and the ceramic layer. This composite structure combines the conductive properties of metal with the stress-absorbing properties of glass, enabling both high capacitance and structural reliability
2Volume of moving object
If the thickness of ceramic layers and internal electrodes is reduced to decrease component size, then component size decreases, but delamination becomes more likely due to increased sintering shrinkage difference
Solution Approach 1:
The glass phase serves as an intermediary layer that compensates for the increased sintering shrinkage difference between thin ceramic layers and thin internal electrodes. This mediator absorbs the differential shrinkage stress, preventing delamination even when both ceramic and electrode thicknesses are reduced
Solution Approach 2:
The glass phase changes the physical parameters at the interface by providing a material with intermediate thermal expansion and sintering shrinkage characteristics between the ceramic and metal, thereby reducing the parameter mismatch and preventing delamination in thin-layer structures
3Reliability
If glass phases are formed to penetrate through internal electrodes to reduce stress, then thermal stress is reduced, but internal electrodes are broken off causing capacitance decrease
Solution Approach 1:
The harmful penetrating glass phases that cause internal electrode breakage are extracted or removed from the structure. Instead, a non-penetrating glass phase layer is formed only at the interface, eliminating the capacitance-reducing breakage while retaining the stress-relief function
Solution Approach 2:
The glass phase is localized specifically at the interface between the internal electrode and ceramic layer, rather than penetrating through the entire internal electrode. This local concentration of glass phase provides stress relief exactly where needed at the interface without compromising the structural integrity and electrical function of the internal electrode
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 solution enhances thermal shock resistance and maintains electrostatic capacitance performance, enabling the reduction in size and increase in capacitance of laminated ceramic components without structural defects like delamination and cracking.
Implementation Method 1
The glassy substance deposited as described above suppresses the shrinkage of the internal electrodes 3, reduces thermal stress at the interfaces between the internal electrodes 3 and the ceramic layers 2
Implementation Method 2
the ceramic constituting the ceramic layer section and the metal constituting the internal electrode section are different from each other in coefficient of thermal expansion
Implementation Method 3
a plurality of columnar members made of a ceramic are formed in the internal electrodes... helps to relax thermal stress and reinforce joints
Data Source
AI summary
A laminated ceramic capacitor including a laminated body having a plurality of stacked ceramic layers and internal electrodes located between the ceramic layers. The internal electrodes have a plurality of ceramic columnar members formed therein, which project into the internal electrodes from interfaces between the ceramic layers and the internal electrodes, but do not penetrate in the thickness direction of the internal electrodes.