NdFeB Magnetic Powder Preparation Without Crushing Steps
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Solution Overview
Problem
Current methods for preparing NdFeB magnetic powders are inefficient due to the need for crushing processes, high manufacturing costs, and limitations in particle refinement, particularly when using rare earth oxides and metallic boron, and the methods require additional physical processes and materials.
Innovation Solution
A method utilizing neodymium praseodymium (Nd, Pr) mixed oxide extracted from waste permanent magnets, combined with iron oxide and boron oxide, undergoes calcination and hydrogen reduction to produce NdFeB magnetic powders with small average particle sizes through calcium reduction, eliminating the need for additional crushing and using only oxides and calcium as reducing agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional strip/mold casting or melt spinning methods are used to prepare NdFeB magnetic powders, then magnetic properties can be achieved, but the process requires time-consuming crushing operations and additional physical processing steps
Solution Approach 1:
The invention changes the chemical state parameters of the starting materials from metallic form to oxide form (Nd2O3, Fe2O3, B2O3). This parameter change enables the materials to be directly sintered into magnetic powders without requiring crushing operations, thereby improving productivity and simplifying the process while maintaining magnetic properties
Solution Approach 2:
The invention extracts and eliminates the crushing process from the conventional manufacturing flow. By using oxide materials that can be directly sintered, the time-consuming crushing step is completely removed from the process, reducing both time and equipment complexity
2Reliability
If rare earth oxides and metallic boron are used in conventional methods, then magnetic materials can be synthesized, but manufacturing costs increase
Solution Approach 1:
The invention changes the form of rare earth materials from metallic neodymium to neodymium oxide (Nd2O3), and boron from metallic form to boron oxide (B2O3). This parameter change allows the use of more cost-effective oxide materials while maintaining the ability to synthesize high-quality NdFeB magnetic powders with reliable magnetic properties
Solution Approach 2:
The invention employs oxide materials that are more economically accessible than their metallic counterparts. By using Nd2O3, Fe2O3, and B2O3 instead of expensive rare earth metals and metallic boron, the manufacturing cost is reduced while still achieving the desired magnetic material synthesis
3Manufacturing precision
If conventional crushing and refinement processes are applied, then particle size can be reduced, but the process becomes more complex and less efficient
Solution Approach 1:
The invention changes the starting material form to oxides that can be directly sintered into fine magnetic powders. This parameter change eliminates the need for mechanical crushing and refinement processes, achieving particle size control through sintering parameters alone, thereby improving manufacturing precision while maintaining high productivity
Solution Approach 2:
The invention extracts and removes the crushing and refinement steps from the conventional process flow. By using oxide materials that directly sinter into fine powders, the complex particle size reduction operations are eliminated, simplifying the process while maintaining control over final particle dimensions
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
This method effectively produces NdFeB-based magnetic powders with average particle sizes of 1 μm or less, reducing manufacturing costs and process complexity while maintaining high magnetic properties, such as saturation magnetization and coercive force.
Implementation Method 1
preparing (Nd, Pr) mixed oxide containing neodymium (Nd) and praseodymium (Pr) in a first precursor preparation step, preparing iron oxide (Fe3O2) in a second precursor preparation step, and preparing boron oxide (B2O3) in a third precursor preparation step
Implementation Method 2
mixing the first mixture with calcium (Ca) to prepare a second mixture in a second mixing step and inducing diffusion while shaping and pressing the second mixture in a shaping step. The method also includes reducing the shaped and pressed second mixture to prepare a magnetic substance containing Nd, iron (Fe), and boron (B) in a calcium reduction step
Implementation Method 3
inducing diffusion while shaping and pressing the second mixture in a shaping step
Data Source
AI summary
A method of preparing a magnet powder, and a magnet powder, are disclosed. The method includes: preparing a neodymium praseodymium (Nd, Pr) mixed oxide containing Nd and Pr; preparing iron (Fe) oxide; preparing boron (B) oxide; mixing the prepared (Nd, Pr) mixed oxide, iron oxide, and boron oxide to prepare a first mixture; mixing the first mixture with calcium (Ca) to prepare a second mixture; inducing diffusion while shaping and pressing the second mixture; reducing the shaped and pressed second mixture to prepare a magnetic substance containing Nd, Fe, and B; powdering the reduced magnetic substance; and removing reduction by-products from the powdered magnetic substance.