R-T-B Magnet Composition Using Co-Ti-Nb Intergranular Phase
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Solution Overview
Problem
Current neodymium-iron-boron magnet materials have low magnetic properties such as remanence, coercivity, and squareness, which are insufficient for high-demand applications.
Innovation Solution
A neodymium-iron-boron magnet composition comprising ≥30.0 wt % of a rare earth element, 0.1-0.3 wt % of Nb, 0.955-1.2 wt % of B, 58-69 wt % of Fe, with specific ratios of Co to Ti, and optionally including Co, Ti, Nd, Pr, and heavy rare earth elements, forming a Co—Ti—Nb phase in the intergranular triangular region to hinder grain growth and enhance magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional neodymium-iron-boron magnet formulas are used, then manufacturing is simpler, but magnetic properties (remanence, coercivity, squareness) remain low
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple elements including rare earth elements (30-35 wt%), Fe (60-65 wt%), Co (1-3 wt%), Nb (0.1-0.3 wt%), B (0.955-1.2 wt%), and Ti (0.15-0.35 wt%). This specific parameter optimization resolves the contradiction by achieving high magnetic properties through controlled compositional parameters rather than through structural complexity
Solution Approach 2:
The patent creates a composite material system combining multiple rare earth elements (Nd, Pr, heavy rare earth elements), transition metals (Fe, Co, Nb, Ti), and boron in specific ratios. This composite approach enhances magnetic properties by leveraging synergistic effects between different elements, resolving the contradiction between simple formulas and high performance
2Reliability
If grain growth is not hindered, then manufacturing is easier, but magnetic properties deteriorate due to coarse grain structure
Solution Approach 1:
The patent uses Nb as an intermediary element that forms a Co-Ti-Nb phase at grain boundaries. This intermediary phase acts as a barrier to grain growth while maintaining manufacturing feasibility through conventional sintering processes. The Nb element mediates between the need for fine grain structure and ease of manufacture
Solution Approach 2:
The patent applies local quality by concentrating Co, Ti, and Nb elements specifically at grain boundaries to form the Co-Ti-Nb phase. This localized element distribution hinders grain growth at critical interfaces without requiring complex manufacturing processes, resolving the contradiction between grain control and manufacturing ease
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 optimized composition achieves significantly improved coercivity and magnetic properties, including remanence and squareness, making the magnet materials suitable for high-demand applications.
Implementation Method 1
the high melting point metals can hinder the growth of grains and refine grains
Data Source
AI summary
The invention discloses an R-T-B magnet and a preparation method thereof. The R-T-B magnet comprises the following components of: ≥30.0 wt % of R, wherein R is a rare earth element; 0.1-0.3 wt % of Nb; 0.955-1.2 wt % of B; 58-69 wt % of Fe, wherein wt % is a percentage of the mass of respective component to the total mass of all components; the R-T-B magnet further comprises Co and Ti; and in the R-T-B magnet, the ratio of the mass content of Co to the total mass content of “the Nb and the Ti” is 4-10. The present invention further optimizes the coordination relationship among the components in the R-T-B magnet, which can prepare a magnet material with relatively high levels of magnetic properties such as remanence, coercivity, squareness and the like.