Magnetic refrigeration material
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Solution Overview
Problem
Conventional magnetic refrigeration materials, such as Gd-containing and LaFeSi compounds, have limitations including small magnetic entropy change, narrow operating temperature range, and high cost, making them impractical for wide applications, especially near room temperature.
Innovation Solution
A magnetic refrigeration material with the composition La1-fREf(Fe1-a-b-c-d-eSi aCo bGa cY dZ e)13, where RE is a rare earth element excluding La, Y is Ge, Sn, B, or C, and Z is Ti, V, Cr, Mn, Ni, Cu, Zn, or Zr, with specific stoichiometric ranges for a, b, c, d, and e, achieving a Curie temperature between 220 K and 276 K and a maximum magnetic entropy change of at least 5 J/kgK under a 2 Tesla field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Gd-containing materials are used as magnetic refrigeration material, then wide operating temperature range is achieved, but magnetic entropy change is small and cost is high
Solution Approach 1:
The patent applies parameter changes by systematically varying the stoichiometric ratios of elements in the La(Fe1-xCoxSi1-yAly)13 compound. Specifically, it optimizes the Co content (x) and Al content (y) to adjust the Curie temperature and magnetic entropy change characteristics, achieving a balance between operating temperature range and refrigeration capacity without using expensive Gd-containing materials.
Solution Approach 2:
The patent employs composite materials by creating a multi-element intermetallic compound La(Fe1-xCoxSi1-yAly)13 that combines the advantages of different elements. The composite structure integrates La for magnetic properties, Fe and Co for Curie temperature control, and Si and Al for structural stability and magnetic entropy enhancement, achieving performance comparable to or exceeding Gd-containing materials.
2Quantity of substance
If LaFeSi materials are used, then larger magnetic entropy change is achieved, but operating temperature range becomes narrow
Solution Approach 1:
The patent applies parameter changes by optimizing the Co and Al substitution ratios in the La(Fe1-xCoxSi1-yAly)13 compound. By carefully controlling the parameters x and y within specific ranges, the Curie temperature is adjusted to achieve both large magnetic entropy change and wide operating temperature range, resolving the contradiction between these two properties.
3Adaptability or versatility
If multiple kinds of materials with different operating temperature ranges are used, then wide temperature coverage is achieved, but system complexity increases
Solution Approach 1:
The patent applies universality by developing a single La(Fe1-xCoxSi1-yAly)13 compound composition that can operate effectively across a wide temperature range (from liquid nitrogen temperature to room temperature and above). This multi-functional material eliminates the need for multiple specialized materials, thereby simplifying the magnetic refrigeration system while maintaining broad temperature coverage.
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 material provides enhanced refrigeration performance with a wide operating temperature range and high relative cooling power, reducing the number of materials needed for a magnetic refrigeration system and enabling applications from home air conditioners to industrial refrigerators.
Implementation Method 1
utilizes magnetic entropy change occurred when the magnetic order of the magnetic material is changed by magnetic field under isothermal conditions
Implementation Method 2
adiabatic temperature change occurred when the magnetic order of the magnetic material is changed by magnetic field under adiabatic conditions
Data Source
AI summary
Provided is a magnetic refrigeration material which has a Curie temperature near room temperature or higher, and provides refrigeration performance well over that of conventional materials when subjected to a field change up to 2 Tesla, which is assumed to be achievable with a permanent magnet. The magnetic refrigeration material is of a composition represented by the formula La1-fREf(Fe1-a-b-c-d-eSiaCobXcYdZe)13 (RE: at least one of rare earth elements including Sc and Y and excluding La; X: Ga and/or Al; Y: at least one of Ge, Sn, B, and C; Z: at least one of Ti, V, Cr, Mn, Ni, Cu, Zn, and Zr; 0.03 ≤ a ≤ 0.17, 0.003 ≤ b ≤ 0.06, 0.02 ≤ c ≤ 0.10, 0 ≤ d ≤ 0.04, 0 ≤ e ≤ 0.04, 0 ≤ f ≤ 0.50), and has Tc of not lower than 220 K and not higher than 27 6 K, and the maximum (-ΔSmax) of magnetic entropy change (-ΔSM) of the material when subjected to a field change up to 2 Tesla is not less than 5 J/kgK.