Method for preparing rare-earth compound with NaZn13 structure by solid state diffusion

Abstract

The invention relates to a method for preparing a rare-earth compound with a NaZn13 structure by the solid state diffusion of an interface, and belongs to the technical field of magnetic refrigeration materials. The method comprises the following steps of: preparing rare earth-enriched intermediate alloy and Fe-base silicon-containing intermediate alloy, processing the Fe-base silicon-containing intermediate alloy into a shape required by a material with the NaZn13 structure, and processing the rare earth-enriched intermediate alloy into a shape corresponding to that of the Fe-base silicon-containing intermediate alloy, so that the rare earth-enriched intermediate alloy can cover the surface of the Fe-base silicon-containing intermediate alloy; covering the surface of the Fe-base silicon-containing intermediate alloy by the rare earth-enriched intermediate alloy sheets to form a diffusion couple with a smooth combination surface; and after annealing the diffusion couple, taking the diffusion couple out, and quenching by using ice water to obtain rare earth-transition group metal compound which has the shape of the Fe-base silicon-containing intermediate alloy and the NaZn13 structure on the surface of the Fe-base silicon-containing intermediate alloy of the combination surface of the diffusion couple. By the method, the problem of poor machining performance of the rare earth-transition group metal compound is solved, and the method can be used for a magnetic refrigeration air-conditioning technology and a magnetic refrigeration technology.

Description

technical field [0001] The invention belongs to the technical field of magnetic refrigeration materials, and in particular provides an intermediate alloy with a single NaZn alloy formed by solid-state diffusion at the interface. 13 Structure and methods of specific shapes of rare earth-transition metal-silicon compounds. Background technique [0002] In recent years, since magnetic refrigeration technology is considered to be a new generation of environmentally friendly, efficient and energy-saving refrigeration technology, 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. However, NaZn is directly obtained from the rare earth-iron-cobalt-silicon melt by melting casting met...

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Problems solved by technology

But with NaZn 13 Structural rare earth-iron-cobalt-silicon compounds have poor processability. In these documents, it has been proposed to use low-temperature annealing to decompose the 1:13 phase into Fe, and then high-temperature annealing after processing into sheets to obtain the 1:13 phase

The problem is that, firstly, powder metallurgy itself has higher requirements for raw materials than melting casting annealing, and the cost is high; secondly, because rare earth-iron-cobalt-silicon compounds are easy to oxidize, annealing requires a vacuum or an inert gas environment

The document with the patent number 200910235566.1 uses an induction furnace to prepare a large-scale carbon-containing rare earth-iron-cobalt-silicon compound with a size of more than 3mm, and the annealing time is greatly shortened, but there is also no subsequent processing method for the material, which cannot meet the requirements of the magnetic refrigerator shape requirements

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