"The biggest achievement of our research is to overcome the mass production of rare-earth-based magnetic refrigeration materials, to allow water and other environmentally friendly media to exchange heat, and to completely eliminate Freon refrigerants." Recently, a researcher at the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences In the interview, Liu Jian told reporters that the project led by the Natural Science Foundation of Zhejiang Province was formally concluded. The research group completed the "Study on the Directional Solidification Microstructure Control and Magnetic Refrigeration Performance of Lanthanum-Iron-Silicon Alloys" to make the industrialization of magnetic refrigeration technology more One step closer.
Solving mass production problems is expected to make Freon "retire" after nearly a century
In recent years, sustainable development has put forward higher requirements on traditional vapor compression refrigeration technology in terms of environmental protection and energy efficiency. The development of environmentally friendly, energy-saving and efficient new refrigeration technologies has become one of the effective solutions.
Therefore, scientists were inspired by the magnetocaloric effect, a thermal phenomenon caused by the change in the magnetic moment ordering of magnetic materials under a changing magnetic field, and proposed a new refrigeration technology that replaced the traditional refrigerant Freon. The principle is that when the magnetic material is magnetized, the order of the magnetic moment increases, the magnetic entropy decreases, the temperature rises, and the heat is released to the outside; when the magnetic material is demagnetized, the order of the magnetic moment decreases, the magnetic entropy increases, and the temperature decreases. Absorbs heat from the outside.
However, in research, scientists have found that traditional magnetic refrigeration materials, due to their fragility and other reasons, have brought great difficulties to the preparation. "Often in the process of making tablets, magnetic refrigeration materials will break" Liu Jian said that with the support of the Zhejiang Provincial Natural Science Foundation, the research group carried out research on the "brittle" problem, and proposed a new composite structure prepared by blending lanthanum-iron-silicon alloy with high thermal conductivity and high toughness metal. Topic.
After hundreds of experiments and modifications, as of the conclusion of the project, the research team has made innovations in solidification preparation methods, composition and organization control, and the construction of new refrigeration concepts. It has made breakthroughs in the application of magnetic refrigeration materials. Has brought hope for large-scale industrialization of magnetic refrigeration materials.
High-performance metal-based magnetic refrigeration composite material
Provincial funds become "knock brick" project follow-up results in line with enterprise application
After the completion of the provincial fund project, Liu Jian also applied for the national project of magnetic refrigeration material genetic engineering on this basis, and co-organized and led the rare earth magnetic engineering materials laboratory with other researchers, focusing on rare earth permanent magnets and rare earth magnetic refrigeration materials. And further research on rare earth magnetic nanomaterials.
"The Provincial Fund is both the" first bucket of gold "and a" knocker "for young scientists." Speaking of the support of the Natural Science Foundation of Zhejiang Province, Liu Jian believes that the support of the provincial fund is the "first bucket of gold" for young scientists. After many young scientists received the support of the provincial fund, their research results have been extended and further supported by the national fund.
Not only that, Liu Jian's research group also actively connected with enterprises, and successively reached cooperation with Hengdian Dongci, Haier Group, etc., and started an "article" around the industrialization of rare earth magnetic refrigeration materials. "As far as we know, domestic companies are also starting to deploy magnetic refrigeration materials such as refrigerators, but magnetic refrigeration materials are constrained abroad." During contact with enterprises, Liu Jian keenly discovered market pain points: high prices for foreign materials and performance indicators Big fluctuations.
Focusing on the key indicators of magnetic refrigeration materials, Liu Jian's research group actively introduced material genetic engineering methods on the basis of the project of directional solidification microstructure control and magnetic refrigeration performance of lanthanum-iron-silicon alloys, using its high-throughput, high-volume one-time preparation The advantage is that a large amount of material structure data has been accumulated in a short time, so that magnetic refrigeration materials with better performance than similar foreign countries have been prepared.
"In terms of temperature changes, our prepared materials can be accurately controlled within 1K (Kelvin), which is far better than the foreign 3K (Kelvin) indicators." Liu Jian told reporters that the magnetic refrigeration materials prepared by the research group are sensitive to changes in temperature and temperature. The three key indicators of zone control and temperature span are better than similar foreign materials, and the price is only one tenth of foreign products, which has attracted high attention from enterprises.