Preparation method for rare earth ferrous alloy compound with NaZn13 type structure

Abstract

The invention provides a preparation method for a rare earth ferrous alloy compound with a NaZn13 type structure. The method comprises: using high frequency induction to heat a rare earth ferrous alloy ingot, to make the rare earth ferrous alloy ingot induced and molten to a rare earth ferrous alloy melt, the rare earth ferrous alloy melt entering a cooling medium for slow directional solidification, to prolong the stay duration in the temperature interval of the peritectic reaction thereof, so that [alpha]-Fe and liquid phase which is rich in rare earth phase are fully reacted, and a magnetic-thermo functional phase with the NaZn13 type structure is directly formed in one step, showing a good magnetic refrigeration characteristic. The method greatly simplifies a preparation process, and is advantaged by short production process, high effect, and energy conservation, and the method has good application prospect in the field of magnetic refrigeration materials.

Description

technical field [0001] The invention relates to the technical field of magnetic refrigeration materials, in particular to a 13 A preparation method of a rare earth iron-based alloy compound with a type structure. Background technique [0002] Refrigeration and cryogenic technology play a very important role in the development of the national economy. In recent years, due to the destructive effect of freon used in traditional gas refrigerants on the ozone layer in the atmosphere, it has been banned internationally. The development of new environmentally friendly refrigeration technologies has become a research hotspot around the world. [0003] Magnetic refrigeration technology is a green technology that uses magnetic materials as working fluids and utilizes the magnetocaloric effect of the material itself for refrigeration. It has no pollution, high entropy density, small size, simple structure, low noise, high efficiency and low power consumption. characteristics have att...

AI Technical Summary

Problems solved by technology

Although subsequent reported techniques such as melting-quick quenching, rapid solidification, and melt drawing have greatly shortened the subsequent annealing time of as-cast samples, it is still impossible to directly obtain NaZn 13 1:13 phase of the type structure

[0009] Some researchers (M.Katter et al.IEEE Trans.Magn., 2008; 44:3044&4th Int.Conf.onMagnetic Refrigeration at Room Temperature, Baotou, China, 2010,ⅡF-ⅡR:23-28) proposed to use powder metallurgy combination Re-annealing method prepared with NaZn 13 Rare earth iron-based compounds with type structure, and pointed out that using low temperature annealing to decompose and high temperature annealing recovery can improve the processing performance of the compound. However, the problem is that powder metallurgy itself has higher requirements for raw materials than melting casting annealing, and the cost is high. Secondly, the sample annealing needs Vacuum or inert gas environment, more than two high-temperature annealings greatly increase the complexity and cost of the preparation process, and the performance stability of the sample becomes poor after multiple heat treatments, and the practicability is greatly reduced

Although this method can directly obtain the 1:13 phase, and to some extent avoid the problem of difficult subsequent processing of the material, the preparation process of the prefabricated alloy by this method is relatively complicated, and the requirements for the surface finish of the prefabricated alloy are relatively high, and subsequent diffusion is still difficult. High temperature and long time annealing

[0011] In addition, Jiangsu University reported that a high-performance single-phase rare earth-iron-based magnetic refrigeration material was rapidly prepared by a composite method combining ultrasonic gas atomization method, short-time annealing and rapid sintering (Chinese Patent Publication No. CN103639415A), but the method requires Preparation equipment is expensive

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