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还原扩散法制备Sm2Fe17Nx磁粉的研究 总被引:3,自引:0,他引:3
研究了还原扩散法制备Sm2Fe17Nx磁粉过程中,还原扩散反应温度和时间对Sm2Fe17合金单相性的影响,以及Sm2Fe17合金渗氮过程中渗氮温度和时间对Sm2Fe17Nx磁粉性能的影响.结果表明当还原扩散反应温度为1423K、反应时间为5小时能得到均相单一的Sm2Fe17合金;在728K温度下渗氮3.5小时后,400目~500目的Sm2Fe17Nx磁粉的各项磁性能达最大值Br=0.8943T,Hc=325.8kA/m,Hcj=420.3kA/m,(BH)max=78.6kJ/m3. 相似文献
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通过X射线衍射、 差热-热重(DTA-TG)联用仪以及磁测量等手段研究了 Sm2 Fe17化合物及其氮化物的相结构和磁性.通过对Sm2 Fe17化合物的DTA-TG分析可以得到:当温度从室温(约300 K)升至1473 K的过程中,在N2保护的条件下,N原子扩散进入Sm21 Fe17化合物中,在温度为700 K左右时Sm2 Fe17化合物吸氮反应最剧烈,吸氮的结果使得Sm2 Fe17 Nx化合物的居里温度显著提高.随着温度的继续升高,在吸氮反应的同时,Sm2 Fe17 Nx化合物变的不稳定,部分分解为SmN化合物和Fe.对实验结果的分析可以得出,该化合物在接近熔点的1473 K以下只存在Th2 Zn17型结构,不存在Th2 Ni17型结构. 相似文献
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放电等离子烧结技术制备Sm2Fe17Nx烧结磁体的研究 总被引:1,自引:0,他引:1
采用放电等离子烧结技术制备了Sm2Fe17Nx烧结磁体,考查了压力、烧结温度和升温速率对烧结磁体性能的影响.结果表明:随压力的增加,磁体的致密度显著提高,但Sm2Fe17Nx分解成SmN、α-Fe和N2的程度加剧,造成磁体的矫顽力明显下降,在1GPa的高压下烧结时,超过200℃后磁体的矫顽力就下降很快,说明高压促进了Sm2Fe17Nx的低温分解;采用升温速率为450℃/min的快速烧结工艺,发现未能有效地抑制Sm2Fe17Nx的分解. 相似文献
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采用熔炼法制备了Pr2Fe17-xAlx系列化合物。利用X射线衍射和MPMSXL-7型磁强计对样品相结构和磁熵变进行了研究。结果表明:Pr2Fe17-xAlx系化合物保持了Th2Zn17型菱方结构,其居里温度可通过成分微调达到室温附近;Pr2Fe17-xAlx系化合物在居里点附近发生的相变属于二级相变,并在较宽温区范围内保持了较大的磁熵变。该化合物在2.0T外场下的最大磁熵变达到纯金属Gd的60%左右,且其化学性质稳定,制冷温区宽,价格低,是一类具有较大应用潜力的新型室温磁制冷工质材料。 相似文献
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通过采用粉末冶金法及密封氮化的方法,对添加不同钐含量的Sm2Fe17型合金及其氮化物的组织形貌、物相组成与结构及磁性能进行了研究。结果发现,多补偿添加25%钐可以使Sm2Fe17型合金退火态的α—Fe含量小于2%。Sm-Fe合金冶炼后的主相均表现为菱方Th2zn17型结构,但快冷时优先沿{300}和{220}面长大。氮化后Sm2Fe17晶格膨胀形成Sm2Fe17N,主相,而α—Fe的X射线特征峰未见明显移动。Sm14.2FeB58合金晶胞膨胀相对较小,而Sm12.8Fe87.2晶胞膨胀较大,在氮化20h时有最大△V/V=8.36%:氮化增加合金中的α—Fe含量。Sm14.2Fes5.8N,的剩磁最高为59.5Am^2/kg,S1l0.5Fe89.5Nx磁化强度最高值为193.6Am^2/kg,Sm12.8Fe87.2Nx合金的所有磁性能值基本分布在Sm14.2Fe85.8Nx和Sm10.5Fe89.5Nx的值之间。 相似文献
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A three-dimensional finite element micromagnetic algorithm was developed to study the magnetization reversal of the SmCo5/Sm2Co17 based magnets. The influences of the microstructure and magnetic parameters on the coercivity were studied based on the model consisting of 64 irregular cells according to the experimental microstructure. Numerical results show that the coercivity increases with increasing the 2: 17-type cell size. Large cell boundary thickness leads to small coercivity. The drop of anisotropy constant of 1:5 phase leads to the coercivity reducing, while the effect of exchange constant of 1 : 5 phase on coercivity is contrary to that of exchange constant. The calculated field dependence of coercivity can be predicted by an inhomogeneous domain - wall pinning model. The microstructure parameter was analyzed by comparing the calculated coercivity. 相似文献
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Preparation of Sm_2Fe_(17)Alloys in Ca-Sm_2O_3-Fe System 总被引:1,自引:0,他引:1
Sm2Fe17alloyisanimportantprecursorforthe preparationofSm2Fe17Nxmagnet.Sincethenitrogen containedSm2Fe17(Sm2Fe17Nx)alloy,asapermanent magnetmaterial,possessesahigherCurietempera ture,largeranisotropyfield,betterresistancetooxi dationandthermalstability,and… 相似文献
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Bulk Sm2Fe17Nx sintering magnet was fabricated by spark plasma sintering(SPS) technique. The effects of sintering pressure and sintering temperature on the magnetic properties of the Sm2Fe17Nx magnet were investigated. As a result, the density of the magnet is obviously improved with the increase of sintering pressure, but the coercivity drops since Sm2Fe17Nx has decomposed into SmN, α-Fe and N2. When sintering temperature was only above 200 ℃ under 1 GPa sintering pressure, the coercivity even begins to decrease, which indicates that high pressure promotes the decomposition of the Sm2Fe17Nx at lower temperature. The decomposition is also proved by the decrease of nitrogen and increase of α-Fe in the magnets. 相似文献
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Sm2Fe17Nx稀土永磁材料的研究现状及进展 总被引:1,自引:0,他引:1
简要分析了Sm2Fe17Nx的晶体结构、内禀磁特性和N原子与磁性能的关系。着重介绍了Sm2Fe17Nx永磁材料的制备方法以及目前制备工艺存在的问题,并指出了其研究和发展趋势。 相似文献
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High performance Sm2Fe17Nx magnetic powders were fabricated by ball-milling method and were compacted using spark plasma sintering(SPS) technique.Effects of processing conditions on the magnetic properties and decomposition dynamic of the magnets were investigated.It is found that higher sintering temperature improves the densification of the magnets, while deteriorates their magnetic properties simultaneously due to the decomposition of the Sm2Fe17Nx.Sintering at lower temperature can preserve the crystal structure of Sm2Fe17Nx compound, while the powders cannot be consolidated into a fully dense compact.An increased compressive pressure leads to better magnetic properties and higher density for the magnet at the same sintering temperature. 相似文献