Iron-Chromium-Cobalt Magnet Microstructure for Higher Energy Product
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Solution Overview
Problem
Iron-chromium-cobalt permanent magnets face challenges in meeting the required magnetic characteristics, particularly maximum energy product, due to the formation of titanium carbide and/or titanium nitride precipitation phases, which are difficult to control in existing production methods.
Innovation Solution
The development of an iron-chromium-cobalt alloy magnet with a controlled number density of Ti-enriched phases and a squareness ratio greater than 0.72, achieved through an additive manufacturing method that restricts the formation of coarse precipitates at grain boundaries, resulting in improved magnetic characteristics and a method for producing such magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional casting or sintering methods are used to produce iron-chromium-cobalt magnets, then production cost and manufacturing simplicity are improved, but magnetic characteristics (maximum energy product) deteriorate due to formation of coarse Ti-enriched precipitation phases
Solution Approach 1:
The invention changes the thermal processing parameters by introducing a specific two-stage heat treatment process: first heating to 700-900°C to dissolve Ti-carbide/nitride precipitates, then rapidly cooling at 5-50°C/min to suppress re-precipitation. This parameter change transforms the microstructure from coarse precipitates to fine dispersed Ti-enriched phases, achieving maximum energy product of 5.4 MJ/m³ or higher while maintaining manufacturing feasibility
Solution Approach 2:
The invention applies periodic thermal action through the two-stage heat treatment process: a heating stage to dissolve precipitates followed by a rapid cooling stage to freeze the fine structure. This periodic thermal cycling prevents the formation of coarse Ti-enriched phases while maintaining production efficiency, resolving the contradiction between ease of manufacture and magnetic characteristics
2Manufacturing precision
If heat treatment is applied to dissolve Ti-carbide/nitride precipitates, then magnetic characteristics are improved, but production time and energy consumption increase
Solution Approach 1:
The invention optimizes heat treatment parameters by selecting a relatively low temperature range (700-900°C) and limiting holding time to 1-10 hours, followed by rapid cooling. This parameter optimization achieves effective dissolution of Ti-carbide/nitride precipitates and formation of fine Ti-enriched phases while minimizing production time and energy consumption, achieving maximum energy product of 5.4 MJ/m³ or higher
3Manufacturing precision
If rapid cooling is applied after heat treatment, then fine dispersed structure is achieved improving magnetic characteristics, but production complexity and equipment requirements increase
Solution Approach 1:
The invention specifies a rapid cooling rate of 5-50°C/min, which is achievable using conventional quenching media such as water, oil, or air. This parameter specification achieves fine dispersed Ti-enriched phases with maximum diameter of 3 μm or less, improving maximum energy product to 5.4 MJ/m³ or higher, while avoiding the need for complex specialized equipment
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 approach results in magnets with enhanced magnetic characteristics, including a higher maximum energy product and reduced defect rates, leading to improved yield and processing stability by inhibiting grain growth and maintaining a finely dispersed structure.
Implementation Method 1
forming an iron-chromium-cobalt alloy magnet by an additive manufacturing method
Implementation Method 2
a dense sintered body can be obtained in a short time without applying a high heat from the outside
Implementation Method 3
the number density of Ti-enriched phases having a maximum diameter of 3 μm or more is, on average, less than 1.0 per 10,000 μm2
Implementation Method 4
maintaining a finely dispersed structure
Data Source
AI summary
The purpose of the present invention is to provide: an iron-chromium-cobalt alloy magnet having improved magnetic characteristics, especially maximum energy product; and a method for producing the same. Provided is an iron-chromium-cobalt alloy magnet, wherein: the iron-chromium-cobalt alloy magnet includes titanium; the number density of Ti-enriched phases having a maximum diameter of 3 μm or greater in a cross-section is, on average, less than 1.0 per 10,000 μm2; and the squareness ratio represented by (BH)ma×/(Br×HcB) exceeds 0.72.