Titanium Core-Shell Magnetic Powder Production
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Solution Overview
Problem
Existing methods for producing titanium-containing rare earth-iron-nitrogen anisotropic magnetic powders do not fully optimize magnetic properties due to the placement and effect of titanium in the production process.
Innovation Solution
A method involving the formation of a precipitate containing titanium in the initial stage, followed by a precipitate free of titanium, which includes steps of calcining, heat treating, reducing, and nitriding to produce anisotropic magnetic powder with improved magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium is added to rare earth-iron-nitrogen anisotropic magnetic powder, then coercive force and residual magnetization are improved, but magnetic properties can still be further improved
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where titanium is concentrated in the core portion of secondary particles while the peripheral portion contains rare earth and iron elements. This localized distribution of titanium enhances coercive force in the core while the peripheral rare earth-iron structure maintains residual magnetization, achieving superior overall magnetic properties compared to uniform distribution
Solution Approach 2:
The patent creates a composite structure within secondary particles by combining titanium-containing core regions with rare earth-iron peripheral regions. This composite approach allows the titanium core to provide high coercive force while the rare earth-iron shell contributes to residual magnetization, achieving synergistic magnetic properties that exceed simple titanium addition
2Ease of manufacture
If a single precipitate containing titanium is formed, then the production process is simplified, but magnetic properties are not optimized
Solution Approach 1:
The patent segments the precipitation process into two distinct stages: first forming a titanium-containing precipitate, then forming a titanium-free precipitate containing rare earth and iron elements. This segmentation allows separate optimization of titanium distribution and rare earth-iron matrix formation, achieving both process feasibility and optimized magnetic properties through controlled sequential precipitation
3Stability of the object's composition
If titanium is uniformly distributed in the magnetic powder, then the structure is homogeneous, but coercive force and remanence are not maximized
Solution Approach 1:
The patent deliberately creates non-uniform local quality by concentrating titanium in the core portions of secondary particles while leaving peripheral portions with rare earth and iron elements. This localized titanium enrichment in specific regions (cores) while maintaining overall structural organization maximizes coercive force through high-titanium regions and preserves residual magnetization through rare earth-iron peripheral regions
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 method results in a rare earth-iron-nitrogen anisotropic magnetic powder with enhanced magnetic properties, including improved coercive force and remanence, by optimizing the distribution and role of titanium in the powder production.
Implementation Method 1
obtaining an oxide containing R, iron, and titanium by calcining the second precipitate
Implementation Method 2
obtaining a partial oxide by heat treating the oxide in a reducing gas atmosphere
Implementation Method 3
obtaining a partial oxide by heat treating the oxide in a reducing gas atmosphere
Implementation Method 4
obtaining an anisotropic magnetic powder by nitriding the alloy particles
Data Source
AI summary
Provided are a method of producing a titanium-containing rare earth-iron-nitrogen anisotropic magnetic powder having good magnetic properties, and secondary particles for a titanium-containing anisotropic magnetic powder. The method includes: obtaining a first precipitate containing R, iron, and titanium by mixing a first precipitating agent with a solution containing R, iron, and titanium, wherein R is at least one selected from Sc, Y, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu; obtaining a second precipitate containing R and iron by mixing, in the presence of the first precipitate, a second precipitating agent with a solution containing R and iron; obtaining an oxide containing R, iron, and titanium by calcining the second precipitate; obtaining a partial oxide by heat treating the oxide in a reducing gas atmosphere; obtaining alloy particles by reducing the partial oxide; and obtaining an anisotropic magnetic powder by nitriding the alloy particles.