Ferrite Sintered Magnet Grain Boundary Ca La Ratio
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Solution Overview
Problem
M-type ferrite sintered magnets face a trade-off between increasing coercivity and residual magnetic flux density, where enhancing coercivity often results in a significant decrease in residual magnetic flux density.
Innovation Solution
A ferrite sintered magnet with magnetoplumbite type ferrite crystal grains and a two-grain boundary containing Ca and La, with a Ca/La atomic ratio of 0.3 to 3.0, and optionally Si, to balance coercivity and residual magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an oxide of Si or Ca is added to increase coercivity, then coercivity HcJ is improved, but residual magnetic flux density Br decreases significantly
Solution Approach 1:
The invention changes the chemical composition parameters by introducing a specific Ca/La atomic ratio range (0.3 to 3.0) in the grain boundary phase, which modifies the magnetic properties to achieve improved coercivity while maintaining residual magnetic flux density
Solution Approach 2:
The invention uses a composite grain boundary phase containing multiple elements (Ca, La, and optionally Si) in specific ratios, creating a composite material structure that balances coercivity enhancement with residual magnetic flux density maintenance
Data Source
AI summary
Provided is a ferrite sintered magnet including: magnetoplumbite type ferrite crystal grains; and a two-grain boundary interposed between the ferrite crystal grains. The two-grain boundary contains Ca and La, and an atomic ratio Ca/La at the two-grain boundary is 0.3 to 3.0.