Ferrite Magnet Orthoferrite Phase Composition Optimization
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Solution Overview
Problem
Conventional ferrite magnets face challenges in achieving high residual magnetic flux density (Br) and coercive force (HcJ), with La—Co ferrite magnets having Br limited to 4.7 kG and Ca—La—Co ferrite magnets not exceeding the Br of ferrite magnets without additional phases.
Innovation Solution
A ferrite magnet composition including a magnetoplumbite structure and an orthoferrite phase, with specific constitutional proportions of metal elements represented by the formula A1-xRx(Fe12-yMey)z, where A includes Sr, Ba, or Pb, R is a rare earth element like La, and Me is Co or Zn, with orthoferrite-phase content between 0 and 28 mol%, and Si content between 0.002 and 0.15 mass% to enhance Br and HcJ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an orthoferrite phase is contained in ferrite magnet, then coercive force (HcJ) is improved, but residual magnetic flux density (Br) decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition parameters (x, y, z) in the formula A1-xRx(Fe12-yMey)z and limiting the orthoferrite phase content to 0-28 mol%. This quantitative control transforms the orthoferrite phase from a harmful factor to a beneficial component that improves HcJ while minimizing Br loss, resolving the technical contradiction between coercive force improvement and residual magnetic flux density maintenance.
Solution Approach 2:
The patent creates a composite material system combining M-type ferrite phase with controlled orthoferrite phase (0-28 mol%). This composite structure leverages the high coercivity of orthoferrite while maintaining the high residual magnetic flux density of M-type ferrite, achieving both improved HcJ and acceptable Br through phase composition optimization.
2Force
If La and Co are included to improve magnetic characteristics, then coercive force (HcJ) increases, but residual magnetic flux density (Br) is limited to 4.7 kG
Solution Approach 1:
The patent extends the conventional La-Co ferrite composition by introducing additional parameters (A elements, z value ranging from 1.05-1.20) and combining with controlled orthoferrite phase. This multi-parameter optimization allows achieving Br exceeding 4.7 kG while maintaining high HcJ, overcoming the limitations of traditional La-Co ferrite systems.
Solution Approach 2:
The patent develops a composite ferrite system incorporating M-type ferrite, orthoferrite phase, and multiple element substitutions (A, R, Me). This composite approach combines the advantages of different phases and element combinations to simultaneously achieve high Br (>4.7 kG) and high HcJ, surpassing conventional La-Co ferrite performance.
3Quantity of substance
If composition is changed to improve Br and HcJ, then magnetic characteristics are enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent establishes specific parameter ranges (0.71≤x≤0.84, 0.30≤y≤0.60, 1.05≤z≤1.20, orthoferrite 0-28 mol%) that define an optimized composition window. Within these ranges, conventional sintering processes can achieve high Br and HcJ without requiring complex manufacturing steps, balancing performance improvement with manufacturing simplicity.
Data Source
AI summary
This ferrite magnet has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and is characterized in that the composition ratios of the total of each metal element A, R, Fe and Me is represented by expression (1) A1-xRx(Fe12-yMey)z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol %. The invention makes it possible to achieve a ferrite magnet with increased Br.