Laminated Coil Component with Graded Copper Ferrite
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laminated coil components face challenges with small rated current due to magnetic saturation, degraded magnetic characteristics from residual stress caused by thermal expansion differences between ferrite and silver, and increased direct-current resistance from sintering modifiers like SiO2.
Innovation Solution
A laminated coil component with a magnetic section of sintered ferrite material containing Fe, Ni, Zn, and Cu, where the Cu content ratio in the near-conductor region to the central region is 0.2 to 0.5, allowing co-firing with silver-containing conductor paste at reduced CuO content, and heat treatment in an oxygen-poor atmosphere to achieve lower sintering temperatures and reduced internal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintering modifier (SiO2) is mixed in conductor paste to prevent residual stress, then magnetic characteristics are improved, but direct-current resistance increases
Solution Approach 1:
The invention extracts and removes the sintering modifier (SiO2) from the conductor paste formulation. By eliminating this non-conductive additive, the patent achieves low direct-current resistance while using alternative methods (Cu content control and oxygen-poor atmosphere sintering) to prevent residual stress and maintain magnetic characteristics.
Solution Approach 2:
The invention changes the sintering process parameters by conducting firing in an oxygen-poor atmosphere, which enables low-temperature sintering without requiring sintering modifiers. This parameter change allows the conductor paste to achieve sufficient bonding and density without adding SiO2, thereby maintaining low electrical resistance.
2Ease of manufacture
If conventional co-firing in air is used, then manufacturing process is simple, but residual stress degrades magnetic properties
Solution Approach 1:
The invention uses an oxygen-poor atmosphere during the sintering process, which creates a controlled environment that prevents excessive oxidation and enables lower sintering temperatures. This atmospheric modification reduces thermal stress between the ferrite magnetic body and silver conductor, thereby preventing degradation of magnetic properties while maintaining manufacturing feasibility.
3Temperature
If CuO content is reduced for lower sintering temperature, then co-firing with silver becomes possible, but sinterability decreases
Solution Approach 1:
The invention changes the sintering atmosphere parameter to oxygen-poor conditions, which enables effective sintering at lower temperatures without requiring high CuO content. The controlled atmosphere compensates for the reduced CuO sintering activity, allowing co-firing with silver at temperatures below its melting point while maintaining adequate sinterability and mechanical strength.
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
Improves DC superimposition characteristics without increasing direct-current resistance, reduces internal stress, and maintains stable magnetic properties under thermal shock, enhancing the laminated coil component's performance and reliability.
Implementation Method 1
heat treatment in an oxygen-poor atmosphere to achieve lower sintering temperatures and reduced internal stress
Implementation Method 2
residual stress generated in the magnetic body due to a difference in coefficient of thermal expansion between the ferrite material and silver
Data Source
AI summary
A laminated coil component that has DC superimposition characteristics improved without causing an increase in direct-current resistance, and reduces stress which can be generated in a magnetic body. A laminated coil component includes a magnetic section of magnetic layers stacked and a conductor section which has a plurality of conductor pattern layers arranged between the magnetic layers, and interconnected in a coiled shape to pass through the magnetic layers, and which is buried in the magnetic section. The conductor section is composed of a conductor containing silver. The magnetic section is of a sintered ferrite material containing Fe2O3, NiO, ZnO, and CuO. The ratio of the Cu content (in terms of CuO) in a near-conductor section region of the magnetic section to the Cu content (in terms of CuO) in a central region of the magnetic section is 0.2 to 0.5.