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论文类型：期刊论文

发表时间：2010-04-01

发表刊物：KOREAN JOURNAL OF METALS AND MATERIALS

收录刊物：SCIE、Scopus

卷号：48

期号：4

页面范围：357-362

ISSN号：1738-8228

关键字：plasma arc-discharge; ferromagnetic materials; phase transformation; annealing; nanoparticles

摘要：Ferromagnetic Mn-Al nanoparticles were prepared using a plasma arc discharge method. The influence of the process parameters on the vaporization rate, composition, particle size, and magnetic properties of the as-produced nanoparticles was investigated. The Mn content was found to be higher in the nanoparticles than in the corresponding mother materials, although the difference diminished with the reaction time. As the H, content in the reaction gas increased, both the vaporization rate and the particle size increased. With 30 at.% Mn, the average particle diameter was 35.2 nm under a pure Ar gas condition, whereas it was 95.4 nm at a Ar:H(2) ratio of 60:40. With the addition of a small amount of carbon, epsilon-phase nanoparticles were successfully synthesized. After a heat treatment in a vacuum for 30 min at 500 degrees C, the nonmagnetic c-phase was transformed into the ferromagnetic iota-phase, and a very high coercivity of nearly 5.6 kOe was achieved.