Ferrite Composition for Co-firing Copper Conductors
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Solution Overview
Problem
Ceramic electronic components with ferrite materials face challenges in achieving favorable insulation and electrical characteristics when co-firing a Cu-based conductive part with a magnetic body part, due to oxidation and reduction issues at high temperatures, leading to degraded electrical characteristics and magnetic permeability.
Innovation Solution
Adjusting the content of Fe2O3 to 20-48 mol% and optimizing the ratio of Mn to Fe and Mn2O3, while maintaining a reducing atmosphere to prevent Cu oxidation, ensures favorable insulation and electrical characteristics by maintaining Fe2O3 in its trivalent state and improving magnetic permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Cu-based material is used for the conductive part and co-firing is performed with the ferrite material, then production cost is reduced and electrical conductivity is improved, but Cu is oxidized to Cu2O and Fe2O3 is reduced to Fe3O4, degrading insulation performance and electrical characteristics
Solution Approach 1:
The invention changes the chemical composition parameters of the ferrite material by limiting Fe2O3 content to 45-49.5 mol% and adding Mn2O3 (0.1-2 mol%), CuO (5-15 mol%), and ZnO (15-30 mol%). This compositional adjustment allows the material to maintain insulation performance while being fired in a reducing atmosphere that prevents Cu oxidation.
Solution Approach 2:
The invention creates a composite ferrite system combining multiple oxides (Fe2O3, Mn2O3, CuO, ZnO, NiO) with specific ratios. This composite material structure provides both the magnetic properties needed for the magnetic body and the chemical stability required to prevent Fe2O3 reduction, enabling co-firing with Cu-based conductors.
2Strength
If the Fe2O3 content is increased to improve magnetic properties, then magnetic permeability is enhanced, but specific resistance decreases due to reduction to Fe3O4, degrading insulation performance
Solution Approach 1:
The invention optimizes the Fe2O3 content parameter to a specific range (45-49.5 mol%) that balances magnetic permeability and insulation performance. Additionally, Mn2O3 is added as a stabilizing component that prevents Fe2O3 reduction, allowing the material to maintain both high magnetic properties and high specific resistance.
3Reliability
If a reducing atmosphere is used to prevent Cu oxidation during co-firing, then electrical conductivity of the conductive part is maintained, but Fe2O3 is reduced to Fe3O4, degrading the magnetic body part's characteristics
Solution Approach 1:
The invention develops a composite ferrite material containing Mn2O3, CuO, and ZnO in specific ratios that creates a chemically stable system. This composite structure allows the material to be fired in a reducing atmosphere without Fe2O3 reduction, as the combined oxide system maintains compositional stability under reducing conditions.
Solution Approach 2:
The invention changes the chemical composition parameters to include Mn2O3 (0.1-2 mol%) which acts as a stabilizer in reducing atmospheres. This parameter adjustment enables the ferrite material to maintain Fe2O3 in its trivalent state even when fired under reducing conditions necessary for Cu-based conductor stability.
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 approach results in ceramic electronic components with improved specific resistance, insulation performance, and magnetic permeability, ensuring reliable operation and high impedance characteristics even when using Cu as the main constituent for the conductive part.
Implementation Method 1
JP H05-326242 A discloses an electronic component including sintered ferrite composed of Ni-Cu-Zn, Ni-Cu, Ni-Zn or Cu-Zn based ferrite
Implementation Method 2
from the relationship between the equilibrium oxygen partial pressure of Cu-Cu 2 O and the equilibrium oxygen partial pressure of Fe 2 O 3 -Fe 3 O 4 , it is known that there is no region for coexistence of Cu with Fe 2 O 3 at high temperatures of 800°C or more. More specifically, at high temperatures of 800°C or more, Cu is also oxidized to produce Cu 2 O when firing is carried out with an oxygen partial pressure set to such an oxidizing atmosphere that maintains the state of Fe 2 O 3 .
Implementation Method 3
when firing is carried out with an oxygen partial pressure set to such a reducing atmosphere that maintains the state of the Cu metal, Fe 2 O 3 is reduced to produce Fe 3 O 4 .
Data Source
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AI summary
Provided is a ceramic electronic component including a magnetic body part 2 composed of a ferrite material and a conductive part 3 containing Cu as its main constituent, the magnetic body part 2 containing trivalent Fe and divalent elements including at least divalent Ni, and the content of the Fe being 20 to 48% in molar ratio in terms of Fe2O3. The magnetic body part 2 contains Mn in such a way that the ratio of Mn to the total of Fe and Mn is less than 50% in molar ratio each in terms of Mn2O3 and Fe2O3. The magnetic body part 2 and the conductive part 3 are obtained by co-firing in an atmosphere at a pressure equal to or lower than the equilibrium oxygen partial pressure of Cu-Cu2O. Thus, even in the case of co-firing the conductive part 3 containing Cu as its main constituent with the magnetic body part 2, insulating performance can be ensured, and favorable electrical characteristics can be achieved.