Method for even hydrogenation of NaZn13 structured rare earth-iron cobalt silicon material

A technology of iron-cobalt-silicon and rare earths, which is applied in the direction of magnetic materials, inorganic materials, electrical components, etc., can solve the problems that do not involve the uniformity of rare earth-iron-cobalt-silicon compounds, reduce preparation costs, reduce equipment maintenance, and improve safety sexual effect

Inactive Publication Date: 2010-09-01
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, most patent documents do not involve the homogeneity

Method used

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  • Method for even hydrogenation of NaZn13 structured rare earth-iron cobalt silicon material
  • Method for even hydrogenation of NaZn13 structured rare earth-iron cobalt silicon material
  • Method for even hydrogenation of NaZn13 structured rare earth-iron cobalt silicon material

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Experimental program
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Effect test

Embodiment 1

[0037] will have NaZn 13 Structure LaFe 11.5 Si 1.5 The compound was placed in a closed hydrogen annealing furnace, and the vacuum was evacuated to 6×10 -1 Pa, heated to 150°C to 650°C, hydrogen at an atmospheric pressure, hydrogenated for 2 hours to obtain LaFe 11.5 Si 1.5 Hydride. Such as Figure 2 to Figure 9 Shown:

[0038] figure 2 It represents the X-ray diffraction pattern of the hydride obtained by hydrogenating the compound at various temperatures, wherein the abscissa is the diffraction angle, and the ordinate is the diffraction intensity. It can be seen from the figure that when the hydrogenation temperature is 150°C, LaFe 11.5 Si 1.5 The X-ray diffraction pattern of the compound and the original LaFe 11.5 Si 1.5 The ratio of the compound does not change, indicating that at 150 °C LaFe 11.5 Si 1.5 The compound does not absorb hydrogen. However, the X-ray diffraction patterns of hydrogenation at other hydrogenation temperatures are consistent with shif...

Embodiment 2

[0043] will have NaZn 13 Structure LaFe 11.6 Si 1.4 Put the compound into an open hydrogen annealing furnace, firstly pass argon gas for 30 minutes, change the atmosphere in the furnace to an argon atmosphere, and then heat it to 550°C and pass in hydrogen gas for hydrogenation, then ignite and burn hydrogen gas at the outlet of the hydrogen annealing furnace, The hydrogenation time is 2h, and the furnace is cooled after hydrogenation. Randomly selected 3 samples for DSC curve analysis, the results are as follows Figure 10 as shown, Figure 10 Be the LaFe of embodiment 2 11.6 Si 1.4 The DSC curve of the hydride; where the abscissa is temperature and the ordinate is heat flow. The exothermic peaks of the three hydride samples are sharp, with significant first-order phase transition characteristics, and the Curie temperature of the three samples is at the same temperature, indicating that hydrogen is absorbed uniformly at this time.

Embodiment 3

[0045] will have NaZn 13 Structure LaFe 11.6 Si 1.4 The compound was placed in a closed hydrogen annealing furnace, and the vacuum was evacuated to 6×10 -1 Pa, heated to 650°C in vacuum and held for 8 hours, then the sample was cooled to room temperature with the furnace. Then heated to 250 °C, and hydrogen gas at an atmospheric pressure was introduced, and LaFe was obtained after hydrogenation for 4 hours. 11.6 Si 1.4 Hydride. In order to test the uniformity of the activated hydrogen-charged sample, 3 small particles with a weight of about 5 mg were randomly selected in the sample for DSC measurement. The results are as follows Figure 11 shown. Figure 11 Be the LaFe of embodiment 3 11.6 Si 1.4 The DSC curve of the hydride; where the abscissa is temperature and the ordinate is heat flow. It can be seen from the figure that the peaks of the three DSC curves are relatively sharp, and the temperatures corresponding to the peaks are very close, so it can be confirmed th...

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Abstract

The invention discloses a method for the even hydrogenation of NaZn13 structured rare earth-iron cobalt silicon material, which comprises the step: putting rare earth-iron cobalt silicon compound having NaZn13 structure in a hydrogenation furnace for hydrogenation thermal treatment for 2 to 4 hours at the temperature ranging from 400 to 600 DEG C. The method can also comprise the step of putting the rare earth-iron cobalt silicon compound having NaZn13 structure in the hydrogenation furnace for activation once or many times and then for hydrogenation thermal treatment at the temperature ranging from 80 to 600 DEG C for 2 to 4 hours so as to result in the finished product. The rare earth-iron cobalt silicon hybride obtained after hydrogenation according to the preparation method has a crystal structure taking the NaZn13 structure as main phase, which is identical to the crystal structure of original rare earth-iron cobalt silicon compound. The method has the advantages that: the hydrogenation time is short, the rare earth-iron cobalt silicon compound can be certainly subject to even hydrogenation, and all the hybrides of the resultant rare earth-iron cobalt silicon compound have only one magnetic phase transition temperature. Thus, outstanding refrigerating effect of the hybrides of the rare earth-iron cobalt silicon compound during the use thereof in a magnetic refrigerator can be ensured.

Description

technical field [0001] The invention belongs to the technical field of magnetic refrigeration materials, in particular to a uniform hydrogenated NaZn 13 A method for the structure of rare earth-iron-cobalt-silicon materials. Background technique [0002] In recent years, since magnetic refrigeration technology is considered to be one of the next-generation new refrigeration technologies that are environmentally friendly, efficient and energy-saving, the exploration and research of magnetic refrigeration materials with huge magnetic entropy change has attracted great attention. Especially with NaZn 13 The rare earth-iron-cobalt-silicon compound in the phase is recognized as the most practical magnetic refrigeration material due to its low price of raw materials and large change in magnetic entropy. But with NaZn 13 The Curie temperature of the rare earth-iron silicon compound of the structure is very low, so it cannot be applied in magnetic refrigeration technologies such ...

Claims

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Application Information

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IPC IPC(8): B22F1/00B22F9/00H01F1/00H01F1/20
Inventor 龙毅马涛王超伦常永勤叶荣昌万发荣
Owner UNIV OF SCI & TECH BEIJING
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