Sm2Fe17Nx的制备

在研究确定了原材料配比的基础上,采用还原扩散法制备出了 Sm2Fe17合金粉;探讨了反应温度、恒温时间、氮气压力及氮气压力200kPa时温度等因素对氮化反应的影响.当氮气压力为200 kPa、温度为873K、恒温5h时,生成Sm2Fe17N2.874,其氮含量为3.111%.     

还原扩散法制备Sm2Fe17Nx磁粉的研究

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.     

Sm2Fe17Nx稀土永磁材料的研究现状及进展

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。     

放电等离子烧结技术制备Sm2Fe17Nx烧结磁体的研究

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.     

Sm2(Fe,M)17Nx稀土永磁材料的研究进展

综述了Sm2(Fe，M)17Nx永磁材料的最新研究进展，介绍了Sm2(Fe，M)17Nx磁粉及磁体的制备技术，说明用其他元素替换Sm或Fe对材料性能的影响，以及粉末颗粒具有最佳的尺寸和形貌的重要性。并指出放电等离子烧结技术(SPS)有望成为制备Sm2(Fe，M)17Nx致密磁体的一个有效方法。     

Study on bulk Sm2 Fe17 Nx sintered magnets prepared by spark plasma sintering

Abstract

Sm₂Fe₁₇N_x sintered magnets were fabricated by spark plasma sintering (SPS) technique. Effects of sintering pressure, sintering temperature and heating rate on the magnetic properties and crystal structures of the magnets were investigated. The results showed that the density of the magnet was obviously improved with increasing sintering pressure, but the coercivity dropped simultaneously because Sm₂Fe₁₇N_x decomposed into SmN, α-Fe and N₂. The coercivity decreased rapidly when sintering temperature was above 200°C under 1 GPa sintering pressure, which indicated that high pressure promoted the decomposition of Sm₂Fe₁₇N_x even at low temperature. In addition, the decomposition could not be effectively restrained even if the heating rate reached 450°C min^?1.     

Structure and Magnetic Properties of Sm2Fe17Nx Sintering Magnets Prepared by Spark Plasma Sintering

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.     

各向异性Sm12.8Fe87.2Nx粘结磁体的研究

采用粉未冶金法对合金及其氮化物与粘结磁体的组织形貌、物相及磁性能进行了较为详细的研究.结果发现，均匀化退火可以明显减少Sm12.8Fe87.2合金中的富Sm相与α—Fe含量。氮化后Sm2Fe17晶格膨胀形成Sm2Fe17Nx主相，氮化20h内Sm2Fe17Nx相单胞体积膨胀超过6％，在20h有最大值△Ve／Ve=8.36％：氮化后合金中的α-Fe含量增加，未见相应用胞体积膨胀:Sm12.8Fe87.2Nx取向粘结磁体中Sm2Fe17Nx相的006衍射明显增强，而其他衍射及α-Fe的衍射减弱，易轴方向磁体的矫顽力优于磁粉的，而剩磁与最高场下磁化强度值劣于磁粉.     

Preparation of Sm_2Fe_(17)Alloys in Ca-Sm_2O_3-Fe System

Sm2Fe17alloyisanimportantprecursorforthe preparationofSm2Fe17Nxmagnet.Sincethenitrogen containedSm2Fe17(Sm2Fe17Nx)alloy,asapermanent magnetmaterial,possessesahigherCurietempera ture,largeranisotropyfield,betterresistancetooxi dationandthermalstability,and…     

Spark Plasma Sintering Bulk Sm2 Fe17NxMagnets

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.     

还原扩散法制备Sm2Fe17化合物的工艺研究

研究了还原扩散法制备Sm2Fe17化合物工艺中Sm2O3，Ca，CaCl2的配入量对Sm2Fe17合金均相性的影响，并用XRD对产物进行物相分析。结果表明：当反应温度为1423K，反应时间为5h，Sm2O3，Ca，CaCl2的配入量分别为121％，225％，8％时，还原扩散反应比较充分，能得到均相单一的Sm2Fe17化合物。     

Evaluating Acceleration Ability of Electrons of SiO_2 and ZnS in ZnS∶Er Electroluminescence

SinceCoeyandSun[1]discoveredtheinterstitial compoundSm2Fe17Nx,ithasattractedmanyresearch ers′attention.Asakindofpermanentmagneticmate rial,Sm2Fe17Nxexhibitsfairlyhighsaturationmagneti zation(1.54T)[2],highanisotropyfield(14T)under roomtemperatureandhighC…     

用还原扩散法制备Sm2Fe17合金

主要研究还原扩散法(R/D)制备Sm2Fe17合金的工艺和主要影响因素,并通过XRD和SEM等分析测试手段对还原扩散机理作了理论分析和实验研究,得出了还原扩散法制备Sm2Fe17的最佳工艺条件,实验表明在合理的原料配比条件下,1423K保温6小时后快淬可以制得成分单一的Sm2Fe17合金。     

Synthesis mechanism of Sm2Fe17 alloy produced in reduction-diffusion process

Sm₂Fe₁₇ alloy was the precursor of Sm₂Fe₁₇N_x magnetic materials. Reduction-diffusion (R/D) method was a new preparation process for the Sm₂Fe₁₇ alloy, and had been widely employed as a new preparation method for rare earth-transition metal intermetallic compounds. In this text, thermodynamics and kinetics for the synthesis of the Sm₂Fe₁₇ alloy by reduction-diffusion (R/D) method in the Ca-Sm₂O₃-Fe system were analyzed. The related synthesis mechanism of this reaction was investigated in detail by means of scanning electron microscope (SEM). The results showed that the thickness of the Sm₂Fe₁₇ alloy layer versus the reaction time could be fit by the parabola law, and its growth model was determined to be: (L₀-L)²=43.848 t, the diffusion of Sm into Fe proceeded with the formation of the Sm₂Fe₁₇ phase from the very beginning of the reaction, and rich samarium phases, such as SmFe₂ and SmFe₃, were not formed, and the rate-determining step of the R/D reaction was found to be the peritectic reaction between liquid samarium and solid iron.