R-T-B Permanent Magnet Grain Boundary Oxides for Oxygen Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for controlling oxygen content in sintered neodymium-iron-boron (NdFeB) permanent magnets are complex and often compromise magnetic properties, leading to reduced performance in severe service environments due to varying oxygen levels and oxidation issues.
Innovation Solution
An R-T-B based permanent magnet material is developed, where R includes neodymium, praseodymium, gadolinium, holmium, dysprosium, or terbium, T comprises iron and other transition metals, and B is boron, with M oxides present in the grain boundary phase to control oxygen content and enhance corrosion resistance and formability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen content is increased to improve corrosion resistance, then corrosion resistance is improved, but magnetic properties are reduced
Solution Approach 1:
The patent applies local quality by introducing M oxides specifically at the grain boundary triple points rather than uniformly throughout the magnet. This localized oxygen enrichment at critical grain boundary regions improves corrosion resistance at the interfaces between grains, while the grain interior maintains its original magnetic properties. The selective placement of oxygen at the most vulnerable locations (grain boundaries) resolves the contradiction between improving corrosion resistance and preserving magnetic properties.
Solution Approach 2:
The M oxides act as an intermediary substance that mediates between the conflicting requirements of corrosion resistance and magnetic properties. By introducing M oxides as a intermediate phase at grain boundaries, the patent creates a protective barrier that improves corrosion resistance without directly affecting the magnetic matrix. This intermediary approach allows the system to achieve improved corrosion resistance while maintaining the magnetic properties of the bulk material.
2Manufacturing precision
If complex oxygen control methods are used to control oxygen content, then oxygen content is controlled, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-introducing M oxides into the powder mixture before sintering. This preliminary incorporation of oxygen sources into the starting materials eliminates the need for complex post-processing oxygen control methods. The M oxides are already present in the powder blend, so during sintering they naturally release oxygen to the grain boundaries without requiring additional complex control mechanisms, thereby simplifying the overall manufacturing process while achieving precise oxygen content control.
Solution Approach 2:
The M oxides serve a self-service function by automatically releasing oxygen to the grain boundaries during the sintering process based on the thermodynamic conditions. This self-regulating mechanism eliminates the need for external complex control systems to manage oxygen content. The M oxides autonomously provide the necessary oxygen to grain boundaries during processing, simplifying the manufacturing process while achieving precise oxygen control.
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 R-T-B material effectively controls oxygen content at grain boundaries, improving corrosion resistance and formability without compromising magnetic properties, thus enhancing the application performance and product quality of NdFeB magnets.
Implementation Method 1
M oxides are present in a grain boundary phase of the permanent magnet material
Data Source
AI summary
An R-T-B based permanent magnet material, a preparation method therefor and use thereof are provided. The R-T-B permanent magnet material forms M oxides at the grain boundary triple point, such that oxygen is enriched at the grain boundary triple point, thereby accurately controlling the oxygen content in the magnet. The permanent magnet material and the preparation method of the present disclosure can prepare products with strong corrosion resistance under the condition of unchanged magnetic properties, and improve the formability in the pressing process, thereby improving the qualified rate of the products.