Ferrite Sintered Magnet Composition for Rotating Electric Machines
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Solution Overview
Problem
Ferrite sintered magnets without rare earth elements and Co face challenges in achieving high residual magnetic flux density while maintaining coercive force and mechanical strength.
Innovation Solution
A ferrite sintered magnet with a hexagonal M-type Sr ferrite structure, containing specific amounts of B, Zn, Si, Ca, and other elements, optimized to achieve improved residual magnetic flux density and coercive force without rare earth elements or Co, through precise atomic concentration ratios and grain boundary phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ferrite sintered magnet is made without rare earth elements and Co, then material cost is reduced, but residual magnetic flux density deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the atomic concentration ratios of multiple elements (Fe/Sr ratio: 11.3-13.1, B content: 0.005-0.9%, Zn content: 0.01-1.2%, Si content: 0.05-1.3%, Ca content: 0.15-2.0%) to achieve high residual magnetic flux density without rare earth elements. This systematic parameter optimization resolves the contradiction between cost reduction and performance maintenance.
Solution Approach 2:
The patent creates a composite material system combining M-type Sr ferrite main phase with carefully controlled amounts of B, Zn, Si, and Ca elements. This composite approach, where multiple elements work synergistically, enables high residual magnetic flux density (430 mT or more) while avoiding expensive rare earth elements, thus resolving the cost-performance contradiction.
2Quantity of substance
If ferrite sintered magnet is made without rare earth elements and Co, then material cost is reduced, but coercive force deteriorates
Solution Approach 1:
The patent maintains high coercive force (250 kA/m or more) without rare earth elements by optimizing specific parameters: Fe/Sr atomic ratio (11.3-13.1), B content (0.005-0.9%), Zn content (0.01-1.2%), and the composite parameter Z=0.1-3.25. This precise parameter control compensates for the absence of expensive rare earth elements while preserving magnetic performance.
Solution Approach 2:
The patent applies local quality by introducing specific elements (B, Zn, Si, Ca) in controlled amounts to modify local regions of the ferrite structure. These elements locally enhance magnetic properties at grain boundaries and within the crystal lattice, maintaining high coercive force without requiring expensive rare earth elements throughout the entire material.
3Quantity of substance
If ferrite sintered magnet is made without rare earth elements and Co, then material cost is reduced, but mechanical strength deteriorates
Solution Approach 1:
The patent creates a composite material structure where M-type Sr ferrite is combined with controlled amounts of B, Zn, Si, and Ca elements. This composite formulation, with specific ratios (Fe/Sr: 11.3-13.1, Z: 0.1-3.25), provides both high mechanical strength and cost-effectiveness, resolving the contradiction between material cost and mechanical strength.
Solution Approach 2:
The patent optimizes mechanical strength without rare earth elements by controlling key parameters: Fe/Sr atomic ratio (11.3-13.1), B content (0.005-0.9%), Zn content (0.01-1.2%), Si content (0.05-1.3%), and Ca content (0.15-2.0%). This systematic parameter optimization ensures high mechanical strength while maintaining cost reduction benefits.
Data Source
AI summary
A ferrite sintered magnet comprising an M type Sr ferrite having a hexagonal structure as a main phase, wherein the ferrite sintered magnet does not substantially comprise a rare earth element and Co, a content of B is 0.005 to 0.9% by mass in terms of B2O3, and a content of Zn is 0.01 to 1.2% by mass in terms of ZnO.