Clearance type Gd-Si-Ge magnetic cooling material and manufacturing method thereof

Abstract

The invention belongs to the technical field of magnetic cooling material and a manufacturing method thereof, particularly relates to a clearance type Gd-Si-Ge magnetic cooling material and a manufacturing method thereof. The method comprises the steps of batching, smelting and heat treatment; the chemical general formula of the material is clearance type Gd5Si1.4Ge2.6Cx compound, wherein, x is 0.01-2; raw material with a purity more than 99.9at% is placed in an electric arc furnace according to mixture ratio of the Gd5Si1.4Ge2.6Cx and is melted in a turning over manner with the protection of high-purity argon, thus obtaining uniform alloy cast ingots; the melted cast ingots with tantalum sheets are packaged and encapsulated in a vacuumized tube for heat treatment; samples of the cast ingots which goes through the heat treatment is directly placed in liquid nitrogen for quenching from high temperature , thus obtaining the Gd5Si1.4Ge2.6Cx compound; the method also comprises the step of adding interstitial atom C. The material of the invention has lower temperature delay and magnetic lag, better thermal stability and large magnetothermal effect, good repetitiveness and uniformity and stable performance.

Description

technical field [0001] The invention belongs to the technical field of a magnetic refrigeration material and its preparation, in particular to a gap type Gd-Si-Ge system magnetic refrigeration material and a preparation method thereof. Background technique [0002] In 1997, the Ames Laboratory under the U.S. Department of Energy first reported the presence of Gd in 1997. 5 Si 2 Ge 2 There is a huge magnetocaloric effect in the compound (V.K.Pecharsky, & K.A.Gschneidner, Jr., Phys.Rev.Lett.1997, 78, 4494.), under the magnetic field change of 0-5T, the entropy change value at the phase transition can reach 18J / kgK, much higher than the 8J / kgK of pure rare earth metal Gd. Since then, people have actively developed various magnetic refrigeration prototypes, such as the rotary magnetic refrigerator developed by Zimm et al. It is expected to form a beneficial supplement to or even replace various traditional refrigerators in the future. Although the most commonly used magneto...

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Problems solved by technology

From the Gd that has been obtained so far 5 Si 4-x Ge x It can be seen from the magnetic phase diagram of the compound that Gd 5 Si 4 The Curie temperature of the type compound is much higher than room temperature, so it cannot be used as a room temperature magnetic refrigeration material; Gd 5 Si 2 Ge 2 The Curie temperature of the type compound is around room temperature, however, this type of material has a large thermal hysteresis and magnetic hysteresis, which is also unfavorable for practical applications.

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