R-T-B Permanent Magnet Ga Concentration Coercive Force
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Solution Overview
Problem
Current R-T-B based permanent magnets do not achieve sufficient coercive force at room temperature while maintaining residual magnetic flux density, necessitating an improvement in coercive force HcJ without compromising Br.
Innovation Solution
Incorporating Ga into R-T-B based permanent magnets with main phase grains of R2T14B crystal structure and grain boundaries, where 0.030≤[Ga]/[R]≤0.100, and optionally including the R6T13Ga phase in grain boundaries, to enhance magnetic anisotropy and coercive force HcJ at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If Ga concentration is increased to improve coercive force HcJ, then HcJ at room temperature is improved, but residual magnetic flux density Br may decrease
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Ga concentration within the range 0.030≤[Ga]/[R]≤0.100 in the main phase grains. This optimized parameter range enables simultaneous improvement of coercive force while maintaining residual magnetic flux density, resolving the technical contradiction through quantitative parameter optimization rather than qualitative material changes.
Solution Approach 2:
The patent implements local quality by creating a non-uniform Ga distribution within the main phase grains, with higher Ga concentration at the grain boundaries and lower concentration in the grain centers. This localized differentiation allows the grain boundaries to provide enhanced coercive force while the grain centers maintain high magnetic flux density, thus resolving the contradiction between HcJ and Br.
2Force
If Ga is added to improve coercive force, then HcJ increases, but the complexity of composition control increases
Solution Approach 1:
The patent simplifies composition control by establishing a clear quantitative parameter range (0.030≤[Ga]/[R]≤0.100) that guides manufacturing. This parameter specification transforms the complex task of Ga addition into a controlled process with defined boundaries, making it easier to achieve consistent results while improving coercive force.
Data Source
AI summary
The present invention provides an R-T-B based permanent magnet capable of improving a coercive force HcJ while maintaining a residual magnetic flux density Br.The R-T-B based permanent magnet includes Ga. R is one or more selected from rare earth elements, T is Fe or a combination of Fe and Co, and B is boron. The R-T-B based permanent magnet has main phase grains including a crystal grain having an R2T14B crystal structure and grain boundaries formed between adjacent two or more main phase grains, and 0.030≤[Ga]/[R]≤0.100 is satisfied in which [Ga] represents an atomic concentration of Ga and [R] represents an atomic concentration of R in the main phase grains.