Permalloy Magnetic Wire Orientation for High-Field Flux Stability
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Solution Overview
Problem
Existing permalloy strip materials face challenges in maintaining excellent magnetic properties without excessively reducing thickness, leading to increased lamination complexity and eddy current losses, especially in high magnetic field applications.
Innovation Solution
A magnetic wire material composed of a permalloy alloy with controlled crystal orientation, where the angle difference between the axial direction and the axis of easy magnetization is 10° or less in 20% or more of the cross section, produced through wire-drawing and heat treatment, ensuring a high magnetic flux density and permeability without easy saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the permalloy strip material is processed at a high rolling reduction rate to improve magnetic properties, then the magnetic flux density and squareness ratio are improved, but the strip material becomes thinner leading to increased eddy current loss
Solution Approach 1:
The invention changes the processing parameters by using a rolling reduction rate of 80% or more (but less than 95%) combined with specific heat treatment conditions (temperature of 900°C or higher, holding time of 5 minutes or more). This parameter optimization achieves the desired magnetic properties (squareness ratio of 90% or more) while maintaining sufficient thickness to reduce eddy current losses, resolving the contradiction between magnetic property improvement and energy loss reduction.
2Reliability
If the permalloy strip material is processed at a high rolling reduction rate to improve magnetic properties, then the magnetic flux density and squareness ratio are improved, but the lamination steps become more complicated and production cost increases
Solution Approach 1:
The invention optimizes the rolling reduction rate to 80% or more (but less than 95%), which is sufficient to achieve the desired magnetic properties without requiring extreme thinning. This reduces the number of lamination layers needed and simplifies the lamination process, thereby reducing production complexity and cost while maintaining excellent magnetic properties.
3Reliability
If the axis of easy magnetization is oriented in the rolling direction to achieve high magnetic flux density, then magnetic permeability is improved, but magnetization saturates easily at low magnetic field
Solution Approach 1:
The invention uses a rolling reduction rate of 80% or more combined with heat treatment at 900°C or higher for 5 minutes or more. This specific parameter combination achieves a squareness ratio of 90% or more, which indicates that the magnetic flux density is maintained well into the high magnetic field region, delaying saturation and improving the material's ability to handle high magnetic fields while maintaining good magnetic permeability.
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 magnetic wire material effectively prevents magnetization saturation in high magnetic fields while maintaining thickness, reducing lamination steps, and minimizing eddy current losses, suitable for applications requiring high magnetic fields and frequencies.
Implementation Method 1
a heat treatment step of performing a heat treatment on the wire material obtained in the wire-drawing step
Implementation Method 2
a recrystallization texture in which a <100> orientation that is an axis of easy magnetization is oriented in a rolling direction can be obtained by performing a cold working at a rolling reduction rate of 95% or more and then performing a heat treatment at a temperature of 1000°C or higher
Implementation Method 3
an eddy current loss in the permalloy strip material and heat generation caused by the eddy current loss tend to become problems
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a magnetic wire material containing an alloy containing 40 mass% or more and 50 mass% or less of Ni, with the balance being Fe and unavoidable impurities, in which in a cross section of the wire material along an axial direction thereof, a proportion of a crystal structure in which an angle difference between the axial direction and a <111> direction is 10° or less is 20% or more.