Spherical Iron Alloy Powder via Selective Matrix Removal
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Solution Overview
Problem
Current methods for producing spherical iron alloy powders are limited in size range, particularly for ultrafine powders below 10 µm, as atomization techniques are challenging or impossible for particles in the nanometer to several micrometer range, necessitating a new preparation method for achieving desired properties and applications.
Innovation Solution
A method involving rapid solidification of an initial alloy melt with specific compositions, including La, Fe, Cr, V, Al, Ni, Co, Si, Mo, W, and Ti, to create a solid structure with a La-rich matrix and Fe-rich dispersed phase, allowing for the separation of spherical or near-spherical particles with sizes ranging from 5 nm to 50 µm through acid corrosion or oxidation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomization method is used to prepare spherical Fe alloy powders, then the powders have good sphericity and flowability, but the particle size is limited to 10-150 μm and cannot produce ultrafine powders below 10 μm
Solution Approach 1:
The invention changes the fundamental preparation parameter from atomization (liquid metal breaking) to rapid solidification of alloy melt, followed by selective matrix removal. This parameter change enables production of ultrafine spherical powders (5-50 μm) with controlled size distribution that atomization cannot achieve
Solution Approach 2:
The invention uses a composite structure consisting of a matrix phase (e.g., Al-rich or La-rich) and a dispersed particle phase (Fe alloy particles). The matrix serves as a protective medium during solidification and can be selectively removed to release spherical Fe alloy powders, enabling size control in the ultrafine range
2Manufacturing precision
If rapid solidification is used to create La-rich matrix with Fe-rich dispersed phase, then ultrafine spherical particles can be obtained, but additional acid corrosion or oxidation steps are required for particle separation
Solution Approach 1:
The invention extracts the matrix phase (Al-rich or La-rich) from the composite structure through selective acid corrosion or oxidation. This extraction process separates the Fe alloy particles from the matrix, releasing spherical powders with controlled size while removing the supporting structure
Solution Approach 2:
The matrix phase serves as an intermediary medium that enables controlled particle formation during rapid solidification. It protects the dispersed particles during processing and can be selectively removed later, facilitating the release of spherical powders without direct contact between particles during formation
3Ease of operation
If spherical particles are used for powder metallurgy and 3D printing, then flowability and stacking density are improved, but production cost increases due to specialized preparation methods
Solution Approach 1:
The invention segments the alloy structure into a removable matrix phase and a retained dispersed particle phase. This segmentation allows the matrix to be selectively removed, releasing spherical particles that inherit good flowability while the process remains cost-effective through simple acid corrosion or oxidation steps
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 enables the production of ultrafine spherical iron alloy powders with enhanced corrosion and oxidation resistance, improving flowability and powder stacking density, suitable for applications in powder metallurgy, 3D printing, and other fields, while maintaining low production costs.
Implementation Method 1
solidifying the initial alloy melt into an initial alloy solid using rapid solidification technology
Implementation Method 2
the solidified structure of the initial alloy solid includes a matrix phase and a dispersed particle phase; the melting point of the matrix phase is lower than that of the dispersed particle phase
Implementation Method 3
removing the matrix phase from the initial alloy solid and retaining the dispersed phase to obtain spherical or near-spherical iron alloy powder particles
Data Source
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AI summary
The invention relates to a spherical iron alloy powder material, its preparation method, and its uses. By selecting a dominated Fe-La based alloy system and adding special alloy elements for spheroidization precipitation and corrosion resistant, the invention achieves the dispersion of spherical Fe-rich particles containing spheroidization precipitation elements in a La-rich matrix phase during the alloy solidification process. By removing the La-rich matrix phase, spherical iron alloy powder materials with particle sizes ranging from the nanoscale to tens of micrometers are obtained. This method is simple and can produce spherical iron alloy powders with various morphologies, including nanoscale, submicron, and micron sizes. It has excellent application prospects in fields such as powder metallurgy, metal injection molding (MIM), 3D printing, magnetic materials, heat-resistant materials, high-temperature alloys, coatings, electrical heating materials, wave-absorbing materials, and magnetic fluids.