High-Temperature-Stability Permanent Magnet Material
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Solution Overview
Problem
Current permanent magnet materials, such as Aluminum-Nickel-Cobalt and Samarium-Cobalt, face challenges with temperature stability, coercivity, and magnetic energy product, leading to instability in aerospace and defense applications due to temperature fluctuations, vibration, and magnetic field disturbances.
Innovation Solution
A high-temperature-stability permanent magnet material is developed, comprising a microstructure with a strong magnetic phase and a magnetic phase with spin reorientation transition, isolated from each other, using SmCo compounds with partial replacement by HRE and R elements, achieving low temperature coefficients of coercivity and remanence through encapsulation or interlayer isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If Aluminum-Nickel-Cobalt based magnet is used, then temperature coefficient of remanence is low (about -0.02%/°C), but coercivity is low (less than 2 kOe) and magnetic energy product is low (about 10 MGOe), making it easily disturbed by vibration and magnetic field
Solution Approach 1:
The patent uses a composite microstructure consisting of a strong magnetic phase (SmCo5 or Sm2Co17) and a magnetic phase with spin reorientation transition (RCo5 or R2Co17 where R is a rare earth element). This composite structure combines the high coercivity and magnetic energy product of the strong magnetic phase with the low temperature coefficient of remanence achieved through the spin reorientation transition in the other phase, resolving the contradiction between remanence stability and overall magnetic performance reliability.
Solution Approach 2:
The patent creates different phases with distinct local properties: the strong magnetic phase provides high coercivity and magnetic energy product, while the magnetic phase with spin reorientation transition provides low temperature coefficient of remanence. By spatially separating these functions into different phases within the composite material, the patent achieves both low temperature coefficient of remanence and high reliability simultaneously.
2Reliability
If Samarium-Cobalt based magnet with low temperature coefficient of remanence is used, then coercivity is high (greater than 15 kOe) and magnetic energy product is high (greater than 15 MGOe), but temperature coefficient of coercivity is high (about -0.3%/°C), causing large difference between irreversible and reversible magnetic loss
Solution Approach 1:
The patent employs a composite structure where the strong magnetic phase (SmCo5 or Sm2Co17) provides high coercivity and magnetic energy product, while the magnetic phase with spin reorientation transition (RCo5 or R2Co17) compensates for the temperature dependence of coercivity. The spin reorientation transition in the RCo5 or R2Co17 phase creates a positive temperature coefficient that offsets the negative temperature coefficient of the SmCo phase, achieving low overall temperature coefficient of coercivity.
Solution Approach 2:
The patent utilizes the spin reorientation transition phenomenon in rare earth cobalt phases (RCo5 or R2Co17) which exhibits a positive temperature coefficient of coercivity. By incorporating this phase into the composite structure, the overall temperature coefficient of coercivity is adjusted and reduced, compensating for the temperature sensitivity of the Samarium-Cobalt strong magnetic phase.
3Adaptability or versatility
If permanent magnet material operates in temperature interval from -40°C to 100°C, then it meets practical application requirements, but existing magnets show weak fluctuation affecting precision of instruments
Solution Approach 1:
The patent exploits the spin reorientation transition phenomenon in rare earth cobalt phases, which exhibits a positive temperature coefficient of coercivity and remanence. This parameter change with temperature compensates for the negative temperature coefficients of the Samarium-Cobalt strong magnetic phase, achieving low overall temperature coefficients that maintain instrument precision across the -40°C to 100°C operating range.
Solution Approach 2:
The composite microstructure of strong magnetic phase and magnetic phase with spin reorientation transition enables the material to operate stably across a wide temperature interval while maintaining high measurement precision. The two phases work synergistically to minimize temperature-induced fluctuations in magnetic properties, ensuring instrument precision is maintained throughout the -40°C to 100°C range.
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 solution provides a permanent magnet with improved coercivity and remanence stability across a wide temperature range, ensuring reliable operation in varying environments, with temperature coefficients of coercivity and remanence less than 0.03% and 0.02% per degree Celsius respectively, enhancing the practical application in aerospace and defense fields.
Implementation Method 1
a magnetic phase with spin reorientation transition; the strong magnetic phase and the magnetic phase with spin reorientation transition are isolated from each other
Data Source
AI summary
The present disclosure discloses a high-temperature-stability permanent magnet material and an application thereof. The microstructure of the permanent magnet material comprises a first magnetic phase and a second magnetic phase; the first magnetic phase is a magnetic phase with uniaxial anisotropy, and the second magnetic phase is a magnetic phase with spin reorientation transition; and the first magnetic phase and the second magnetic phase are isolated from each other; and the absolute value of the temperature coefficient of saturation magnetization intensity of the first magnetic phase is less than 0.02%/° C. By means of the permanent magnet material comprising the first magnetic phase and the second magnetic phase, a positive temperature coefficient of coercivity can be obtained, so that obtaining a low temperature coefficient of coercivity can be targeted, regular and universal.