Roksana Muzyka
,
Monika Kwoka
,
(L)ukasz Sm?dowski
,
Noel Díez
,
Grazyna Gryglewicz
新型炭材料
doi:10.1016/S1872-5805(17)60102-1
通过不同的Hummers法和重铬酸钠氧化法,以商业石墨为原料,合成出不同氧含量和官能团的氧化石墨.采用元素分析、FTIR、XPS、SEM和XRD对氧化石墨进行化学和结构表征.重铬酸钾氧化能得到一种氧含量低的氧化石墨,主要形成羟基和环氧基.Hummers法是更有效的一种氧化方法.使用NaNO3氧化2 h,得到的氧化石墨具有最高的氧含量(>40 wt%),形成C—O和C=O键.SEM和XRD结果表明,在这些条件中,Hummers法合成的氧化石墨的石墨层间距最大.因此,用相同的氧化方法,通过改变反应条件能调控氧化石墨的化学结构.
关键词:
石墨
,
改性Hummers法
,
氧化石墨
,
结构
张清
,
李全安
,
井晓天
,
张兴渊
材料工程
doi:10.3969/j.issn.1001-4381.2011.03.016
Mg24Y5相的细化是进一步提高Mg-l0Y合金力学性能的关键.研究了稀土元素sm对Mg-l0Y合金中的Mg24Y5相及其基体组织的细化作用,结果表明:sm的加人,改善了Mg24Y5相的形貌,促进了细小弥散分布的Mg24Y5颗粒相的形成;同时,Sm的加人,通过固溶作用,进一步细化了基体组织;显微组织的改善导致了合金高温下力学性能的提高.
关键词:
Sm
,
Mg-10Y合金
,
组织细化
,
力学性能
李萍
,
杨宗坡
钢铁研究学报
运用L16(44×23)正交设计的实验方法[1],研究了SM(Si-Mn)母合金含量对Fe-SM-C烧结钢力学性能的影响.结果表明:随着SM母合金含量的增加,该烧结钢的硬度单调增大,冲击韧性递减;母合金含量为 6.5 %时,该烧结钢的抗拉强度最佳.
关键词:
母合金
,
力学性能
,
烧结钢
Physical Review B
We demonstrate that the Sm photoluminescence processes (including photoexcitation, transfer, and recombination) for Sm-doped porous Si and Sm-doped SiO2 are different: In the case of Sm-doped porous Si, there is a process by which electron-hole pairs are excited in Si nanoparticles and then transfer to Sm-related luminescence centers to recombine, in addition to the normal process of Sm-doped SiO2. The ratio of contribution to Sm luminescence of such a process to a normal one decreases with increasing the oxidation temperature. However, it has a complicated relationship with the photoexcitation wavelength. We suggest a method which makes it possible to calculate its value.
关键词:
visible-light emission;luminescence;mechanisms;intensity
Zeitschrift Fur Metallkunde
The Sm - Co binary system has been reinvestigated using differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. Eight compounds exist in this system, six of them (Sm9Co4, SmCo2, SmCo3 Sm2Co7, Sm5Co19 and SmCo5) are formed by peritectic reactions, and two (Sm3Co and Sm2Co17) melt congruently. Three eutectic reactions occur in this system. The high-temperature homogeneity ranges for SMCo5 and Sm2Co17 compounds as well as the solid solubility of Sm in Co have been determined.
关键词:
phase-equilibria;redetermination;850-degree-c;cu
Xinguo ZHAO
,
Zhidong ZHANG
,
Zhijun GUO
,
Wei LIU
,
Dianyu GENG
,
Baozhi CUI
材料科学技术（英文）
The alloy with nominal composition Sm-2(Fe0.94Ti0.06)(l7) is prepared by are-melting, hydrogenation and nitrogenation processes. The Sm-2(Fe0.94Ti0.06)(17) alloy has a single phase of Sm-3(Fe, Ti)(29) with the Nd-3(Fe, Ti)(29)-type structure. The corresponding hydride phase with the same phase structure of the parent alloy was formed after a hydrogen decrepitation (HD) process at 300 degrees C. The hydrogenation at 800 degrees C mainly shows a HDDR process. The HD and nitrogenation at 500 degrees C result in increasing the Curie temperature of the alloy by 72 degrees C and by 158 degrees C due to lattice expansions, respectively. The anisotropic and isotropic Sm-3(Fe, Ti)(29)Ny magnets are obtained after HD, HDDR and the consequent nitrogenation, respectively. The optimum magnetic properties of Sm-3(Fe, Ti)(29)Ny powders achieved in the above two processes are: (i) B-r=0.82 T, H-i(c)=4.48 kA/cm, (BH)(max)=54.3 kJ/m(3), (ii) B-r=0.68 T, H-i(c)=8.14 kA/cm, (BH)(max)=66.4 kJ/m(3).
关键词:
材料科学技术（英文）
The alloy with nominal composition Sm-2(Fe0.94Ti0.06)(l7) is prepared by are-melting, hydrogenation and nitrogenation processes. The Sm-2(Fe0.94Ti0.06)(17) alloy has a single phase of Sm-3(Fe, Ti)(29) with the Nd-3(Fe, Ti)(29)-type structure. The corresponding hydride phase with the same phase structure of the parent alloy was formed after a hydrogen decrepitation (HD) process at 300 degrees C. The hydrogenation at 800 degrees C mainly shows a HDDR process. The HD and nitrogenation at 500 degrees C result in increasing the Curie temperature of the alloy by 72 degrees C and by 158 degrees C due to lattice expansions, respectively. The anisotropic and isotropic Sm-3(Fe, Ti)(29)Ny magnets are obtained after HD, HDDR and the consequent nitrogenation, respectively. The optimum magnetic properties of Sm-3(Fe, Ti)(29)Ny powders achieved in the above two processes are: (i) B-r=0.82 T, H-i(c)=4.48 kA/cm, (BH)(max)=54.3 kJ/m(3); (ii) B-r=0.68 T, H-i(c)=8.14 kA/cm, (BH)(max)=66.4 kJ/m(3).
关键词:
sm
Journal of Alloys and Compounds
The isothermal section at 700 degrees C in the Co-rich ternary Sm-Co-B system was determined by means of X-ray diffraction. In this range, nine ternary borides were observed: Sm3Co13B2, SmCo4B, Sm3Co11B4, Sm2Co7B3, SmCo3B2, Sm2Co14B, SmCo12B6, SmCo4B4, SmCo2B2. The first five borides are members of the homologous series Smm + nCo5m + 3nB2n formed by alternative stacking m layers of SmCo5 with n layers of SmCo3B2 along the c-axis. The compound Sm3Co13B2 was not reported in previous isothermal sections found in the literature. (C) 2000 Elsevier Science S.A. All rights reserved.
关键词:
Sm-Co-B;phase diagram;magnetic-properties
Physical Review B
Using only two crystalline electric-field parameters A2(0) and A4(0) and the Sm-Fe exchange field H(ex), the magnetic-anisotropy behavior of the Sm ion in Sm2Fe17N(x) is described. It is shown that a field-induced noncollinear coupling between the spin and orbital moments of the Sm ion takes place during the magnetization process when the external field is applied along the hard axis. This noncollinear coupling causes a very different magnetization process of the Sm moment at T = 0 and 300 K.
关键词:
magnetic-properties;earth
吴之传
,
陶庭先
,
高红军
,
孙志娟
,
吴琦
稀土
doi:10.3969/j.issn.1004-0277.2002.05.007
以偕胺肟基纤维(用L表示)为吸附剂,对Sm(Ⅲ)、NdⅢ)、Pr(Ⅲ)进行螯合吸附,再将螯合后的纤维进行解吸,使稀土离子得到富集.通过实验确定出最佳吸附条件为:温度50℃、时间30～60min、pH 3～4;最佳解吸条件为:0.02～0.08mol*L-1HCl、室温、30～60min.纤维L对Sm(Ⅲ)、Nd(Ⅲ)、Pr(Ⅲ)三种离子的一次吸附的最大量分别为2.99、2.86、4.11 mg*g-1(被吸附离子的初始浓度C0=0.001mol*L-1).L对三种离子均可进行三次以上累积吸附.
关键词:
螯合纤维
,
稀土离子
,
富集
