W-Type Hexagonal Ferrite Composition for Low Coercivity
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Solution Overview
Problem
Current ferrite materials exhibit high coercivity, making them unsuitable for use in inductors and antennas due to low-temperature demagnetization and high magnetic loss, particularly in high-frequency ranges like 6 GHz.
Innovation Solution
A soft magnetic composition with a W-type hexagonal ferrite formula ACaMe2Fe16O27 is developed, where A includes Ba, Sr, Na, K, La, and Bi, and Me comprises Co, Cu, Mg, Mn, Ni, and Zn, with specific mole percentages to achieve low coercivity and high magnetic permeability, formulated into a sintered body, composite body, or paste for coil and antenna applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferrite materials are used, then magnetic strength is maintained, but coercivity becomes too high causing low-temperature demagnetization and high magnetic loss
Solution Approach 1:
The patent changes the chemical composition parameters of ferrite by introducing specific metal elements (Mg, Mn, Ni, Zn, Co, Cu) in controlled amounts to replace部分Fe2+, thereby reducing coercivity from conventional high levels to 100-500 A/m while maintaining magnetic permeability and stability at high temperatures and frequencies up to 6 GHz
Solution Approach 2:
The patent creates a composite ferrite system by combining multiple metal elements (alkaline earth metals A, transition metals Me) with Fe2+ and Fe3+ in a specific W-type hexagonal structure, forming a composite material ACaMe2Fe16O27 that achieves both low coercivity and high magnetic property stability
2Reliability
If high magnetic permeability is achieved, then inductor and antenna performance improves, but magnetic loss increases particularly at high frequencies
Solution Approach 1:
The patent optimizes the ratio of metal elements in the composition ACaMe2Fe16O27, specifically controlling the amounts of Mg, Mn, Ni, Zn, Co, and Cu to achieve the balance point where magnetic permeability is maximized while magnetic loss is minimized at high frequencies up to 6 GHz
Solution Approach 2:
The patent introduces c-axis anisotropy through specific element placement in the W-type hexagonal crystal structure, creating directional magnetic properties that reduce magnetic loss in specific orientations while maintaining high permeability, suitable for antenna applications
3Adaptability or versatility
If ferrite material is used for high-frequency applications, then electromagnetic component functionality is enabled, but temperature-induced demagnetization occurs
Solution Approach 1:
The patent modifies the compositional parameters by incorporating thermally stable metal elements (Mg, Mn, Ni, Zn) that form stable crystal structures in the W-type hexagonal ferrite, maintaining magnetic properties from low temperatures up to high-frequency operating conditions of 6 GHz
Solution Approach 2:
The patent uses conventional, readily available metal elements (Mg, Mn, Ni, Zn, Co, Cu) that are easy to source and process, forming a cost-effective ferrite composition that achieves stable magnetic properties across temperature ranges without requiring exotic or expensive materials
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 composition achieves low magnetic loss and high magnetic permeability in the 6 GHz range, suitable for inductors and antennas by reducing coercivity and maintaining magnetic properties effectively across temperature changes.
Implementation Method 1
an inductor or an antenna is required to have a high magnetic permeability μ′
Implementation Method 2
it is also preferable that an inductor or an antenna has a low magnetic loss component μ′′, and thus the magnetic loss tan δ obtained by a ratio of μ′′/μ′ is required to be low
Implementation Method 3
the soft magnetic composition has a coercivity Hcj of 100 kA/m or less
Data Source
AI summary
A soft magnetic composition that includes an oxide containing a W-type hexagonal ferrite having a compositional formula of ACaMe2Fe16O27 as a main phase, wherein A is one or more selected from Ba, Sr, Na, K, La, and Bi at 4.7 mol % to 5.8 mol %; Me is one or more selected from Co, Cu, Mg, Mn, Ni, and Zn at 9.4 mol % to 18.1 mol %, the Ca is 0.2 mol % to 5.0 mol %, the Fe is 67.4 mol % to 84.5 mol %, and the soft magnetic composition has a coercivity Hcj of 100 kA/m or less.