Sintered NdFeB Magnet Composition Without Dy/Tb for Higher Coercivity
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Solution Overview
Problem
Existing sintered neodymium iron boron magnets face challenges in achieving high coercivity and remanence while avoiding the use of heavy rare earth elements like Dy and Tb, which are prone to price instability due to rare earth policies.
Innovation Solution
Incorporating elements such as Zr, Ti, or Nb into the neodymium iron boron magnet composition, along with other alloying elements like Cu, Ga, Al, and Ti, to form alloy phases that enhance coercivity and remanence without relying on heavy rare earths, through processes involving strip casting, hydrogen decrepitation, jet milling, orientation molding, and sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If Dy and Tb are used to replace Nd to improve coercivity, then coercivity is improved, but remanence is reduced and production cost becomes unstable
Solution Approach 1:
The patent changes the chemical composition parameters by introducing Zr, Ti, or Nb elements at specific concentrations (0.1-1.0% for Zr, 0.1-0.5% for Ti, 0.1-0.3% for Nb) to modify the magnetic properties. This compositional parameter change enables achieving high coercivity without relying on heavy rare earth elements, thus maintaining remanence while improving coercivity
Solution Approach 2:
The patent creates a composite magnetic material system by combining NdFeB base material with additional elements (Zr, Ti, Nb, Cu, Ga, Al) to form a multi-element composite structure. This composite approach allows the material to exhibit enhanced coercivity through the synergistic effects of different elements, particularly through the formation of specific intermetallic phases at grain boundaries that pin domain walls
2Force
If Dy and Tb are used to replace Nd to improve coercivity, then coercivity is improved, but production cost increases due to rare earth policy impact
Solution Approach 1:
The patent replaces expensive heavy rare earth elements (Dy, Tb) with more economically stable and abundant elements (Zr, Ti, Nb). These alternative elements are generally more affordable and less subject to rare earth policy fluctuations, thereby reducing production cost while maintaining the desired coercivity improvement
Solution Approach 2:
The patent modifies the compositional parameters by limiting heavy rare earth content and optimizing the ratios of alternative elements to achieve cost-effective magnet formulation that maintains high coercivity without relying on price-volatile rare earth materials
3Force
If Zr, Ti, or Nb are added to improve coercivity without heavy rare earths, then coercivity and remanence are improved, but manufacturing process complexity increases
Solution Approach 1:
The patent combines multiple alloying elements (Zr, Ti, Nb along with Cu, Ga, Al) into a single integrated compositional system that works synergistically during the conventional sintering process. This merging of elements into a unified formulation allows achieving enhanced magnetic properties without requiring separate processing steps, thus managing manufacturing complexity
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 resulting magnets exhibit increased coercivity and remanence, with coercivity values improving by over 1.0 kOe and 1.3 kOe for zirconium and titanium-containing variants respectively, while maintaining remanence, reducing production costs, and being suitable for large-scale industrial production.
Implementation Method 1
A sintered neodymium iron boron is a permanent magnet with the highest energy density discovered by humans so far
Implementation Method 2
orientation molding and sintering the neodymium iron boron powder in sequence to obtain the sintered neodymium iron boron magnet
Data Source
AI summary
A sintered neodymium iron boron magnet as shown in the formula RxT100-x-y1-y2-zMy1Ay2Bz is provided according to the present application, which specifically includes three different technical solutions.