Method for preparing rare earth magnetic refrigeration material by adopting liquid-phase laser ablation method

Abstract

The invention discloses a method for preparing a rare earth magnetic refrigeration material by adopting a liquid phase laser ablation method. The chemical composition formula of the rare earth magnetic refrigeration material is LnxA1-xMnO3, the element Ln in the compound is rare earth elements such as La, Pr and Sm, the element A is monovalent and divalent metal elements such as Ca, Na, K and Sr,and x is larger than or equal to 0.1 and smaller than or equal to 0.9. Raw material powder of the rare earth magnetic refrigeration material is weighed according to a certain stoichiometric ratio, after sufficient grinding and mixing, the raw material powder is pressed into blocks, the pressed blocks are presintered under a certain temperature condition to form a precursor, the nanoscale high-performance rare earth magnetic refrigeration material is prepared through a laser ablation technology, and finally, sintering is performed under a high magnetic field to obtain the rare earth magnetic refrigeration material. According to the preparation method, the rare earth magnetic refrigeration material with clean surface, good chemical activity and nanoscale size can be obtained, the refrigeration temperature interval is remarkably increased, the refrigeration capacity is enhanced, the high-temperature sintering temperature can be effectively reduced, the high-temperature sintering time canbe effectively shortened, and the preparation process is simple.

Description

technical field [0001] The invention relates to a method for preparing a rare-earth magnetic refrigeration material by a liquid-phase laser ablation method, belonging to the field of high-performance magnetic materials. Background technique [0002] As a new technology for preparing nanoparticles, liquid phase laser ablation technology has attracted much attention. Liquid phase laser ablation (Laser Ablation in Liquid, LAL) is a simple and green nanomaterial preparation technology, which usually only needs to be carried out in water or organic liquid phase conditions. In recent years, LAL has been used to prepare a series of nanomaterials with special morphology and microstructure, and to realize functionalized nanomaterials in the exploration of emerging properties and applications in the fields of optics, display, detection, and biology. one-step preparation. It has been demonstrated that laser ablation of various noble metals precipitated in solvents produces colloidal ...

AI Technical Summary

Problems solved by technology

Magnetic refrigeration materials discovered so far, such as Gd 5 (Si x Ge 1-x ) 4 、La(FeSi) 13 , RMnO 3 , MnFeP 1-x As x , Ni-Mn-X, etc., there are some application limitations

Gd( Si x Gen 1-x ) 4 In order to maintain the giant magnetocaloric effect, the alloy must use high-purity Gd as raw material, which is expensive and requires a strong magnetic field to drive; La(Fe x Si 1-x ) 13 The phase transition temperature of the alloy is low, and the chemical properties are unstable after solution treatment; the Curie temperature of the perovskite-like manganese oxide material is low; MnFeP 1-x As x The preparation process of the compound is complicated, and it contains highly toxic As element. If it is replaced by a non-toxic element, the thermal hysteresis will increase and the efficiency will decrease; the Ni-Mn-X alloy is difficult to control the composition due to the volatilization of Mn element, and it needs long-term high-temperature heat treatment to monophasic tissue