R. T. Malkhasyan
金属学报(英文版)
A new method of corrosion-resistant coating of technical iron is presented. Processingby vibrationally excited hydrogen molecules of the iron surface covered with oxide filmof a-Fe2O3 results in modification of surface by creating a film of amorphous ironon it. The presence of iron films with crystalline and amorphous phases, having thedifferent Fermi levels, leads tO formation of potential differences between them. Thispotential difference is opposite to the external electric field, resulting in decrease ofanode current and increase of corrosion resistance.
关键词:
technical iron
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null
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null
杨慧芬
,
唐琼瑶
,
王传龙
,
张露
,
李甜
中国有色金属学报
为考察红城红球菌(Rhodococcus erythropolis,R. erythropolis)作为赤铁矿捕收剂使用的可能性及效果,对R. erythropolis形貌、细胞壁成分及其吸附前后赤铁矿、石英表面电性、疏水性进行分析,对赤铁矿、石英单矿物以及赤铁矿与石英矿1:1(质量比)混合矿进行浮选实验,对其在赤铁矿表面的吸附状况及吸附机理进行研究.结果表明,杆状R. erythropolis表面既含有非极性基团,又含有极性基团,使得其表面具有较高的负电性和较强的疏水性,因而对赤铁矿的吸附作用明显大于对石英的吸附作用.当以此细菌为捕收剂、在溶液 pH 值为6、R. erythropolis用量为75 mg/L时,赤铁矿的回收率为89.68%,而石英的回收率仅为26.25%.混合矿经过一次浮选,可获得铁品位和回收率分别为50.08%和76.41%的铁精矿.R. erythropolis在赤铁矿表面发生复杂的化学吸附且使赤铁矿颗粒形成疏水絮团,从而证实R. erythropolis可作为赤铁矿的捕收剂使用.
关键词:
R. erythropolis
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微生物
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赤铁矿
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石英
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吸附
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絮团
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捕收剂
材料科学技术（英文）
Structure and magnetostriction of Dy1-xPrxFe2 (0 less than or equal to x less than or equal to 0.5), Dy0.6Pr0.4(Fe1-yTy)(2) (0 less than or equal to y less than or equal to 0.6), and Tb1-zPrz(Fe0.4Co0.6)(2) (0 less than or equal to z less than or equal to 1.0) alloys (T=Co, Ni) have been investigated. It is found that the matrix of the alloys Dy1-xPrxFe2 is a single phase (Dy, Pr)Fe-2 with MgCu2-type structure and the second phase is (Dy, Pr)Fe-3 when x less than or equal to 0.2. The amount of (Dy, Pr)Fe-3 phase increases with increasing Pr content and becomes the main phase when x=0.4. The matrix of Dy1-xPrxFe2 is found to be the (Dy, Pr)(2)Fe-17 phase with Th2Zn17-type structure when x=0.5. It is found that the amount of the cubic Laves phase (Dy, Pr)(Fe, Co)(2) in the Dy0.6Pr0.4(Fe1-yCoy)(2) increases with increasing Co concentration when 0 less than or equal to y less than or equal to 0.6. The substitution of Ni for Fe is nearly not favorable for the formation of the cubic Laves phase (Dy, Pr)(Fe, Ni)(2) in (Dy1-xPrx)Fe-2. The matrix of (Tb1-zPrz)(Fe0.4Co0.6)(2) is a (Tb, Pr)(Fe, Co)(2) phase with the MgCu2-type cubic Laves structure and a second phase of small amount is (Tb, Pr)(Fe, Co)(3) phase when z less than or equal to 0.2, z=0.5 and 1.0. When 0.2
关键词:
Zhijun GUO
,
Zhidong ZHANG
,
Xinguo ZHAO
,
Bowen WANG
,
Dianyu GENG
材料科学技术（英文）
Structure and magnetostriction of Dy1-xPrxFe2 (0 less than or equal to x less than or equal to 0.5), Dy0.6Pr0.4(Fe1-yTy)(2) (0 less than or equal to y less than or equal to 0.6), and Tb1-zPrz(Fe0.4Co0.6)(2) (0 less than or equal to z less than or equal to 1.0) alloys (T=Co, Ni) have been investigated. It is found that the matrix of the alloys Dy1-xPrxFe2 is a single phase (Dy, Pr)Fe-2 with MgCu2-type structure and the second phase is (Dy, Pr)Fe-3 when x less than or equal to 0.2. The amount of (Dy, Pr)Fe-3 phase increases with increasing Pr content and becomes the main phase when x=0.4. The matrix of Dy1-xPrxFe2 is found to be the (Dy, Pr)(2)Fe-17 phase with Th2Zn17-type structure when x=0.5. It is found that the amount of the cubic Laves phase (Dy, Pr)(Fe, Co)(2) in the Dy0.6Pr0.4(Fe1-yCoy)(2) increases with increasing Co concentration when 0 less than or equal to y less than or equal to 0.6. The substitution of Ni for Fe is nearly not favorable for the formation of the cubic Laves phase (Dy, Pr)(Fe, Ni)(2) in (Dy1-xPrx)Fe-2. The matrix of (Tb1-zPrz)(Fe0.4Co0.6)(2) is a (Tb, Pr)(Fe, Co)(2) phase with the MgCu2-type cubic Laves structure and a second phase of small amount is (Tb, Pr)(Fe, Co)(3) phase when z less than or equal to 0.2, z=0.5 and 1.0. When 0.2
关键词:
陶光胤
,
王洪涛
,
王振杰
物理测试
文章利用简易的固相反应法制备了YBa2Cu3O(7-8)(YBCO)样品.利用FD-TX-RT-Ⅱ高温超导转变温度测定仪测试YBCO样品的超导临界温度Tc为90 K左右,并绘制了YBCO的R-T曲线和电镜图像.
关键词:
简易方法
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YBCO
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R-T研究
Journal of Solid State Chemistry
The subsolidus phase relations of R2O3-CaO-CuO ternary systems (R = Nd, Sm, Gd, Tm) have been investigated by X-ray powder diffraction. All samples were synthesized at about 950degrees in air. There exists a ternary compound Ca14-xRxCu24O41 (x = 4 for R = Nd, Gd and x = 5 for R = Sm) and a ternary solid solution Ca2+xR2-xCu5O10 (R = Nd, Sm, Gd, Tm) with a wide composition range Deltax of about 0.6. The compound Ca14-xRxCu24O41 possesses a layered orthorhombic structure and is isostructural to Sr14-xCaxCu24O41. The lattice parameters a and c of the compound are basically independent of the ionic radius of R, while the lattice parameter b and unit-cell volume V decrease substantially with the decrease of the ionic radii of R. The Ca2+xR2-xCu5O10 solid solution is isostructural to Ca2+xY2-xCu5O10, the structure of which is based on an orthorhombic "NaCuO2-type" subcell containing infinite one-dimensional chains of edge-shared square planar cuprate groups crosslinked by the layered cations Ca and R that locate in the inter-chain tunnels. (C) 2002 Elsevier Science (USA). All rights reserved.
关键词:
R2O3-CaO-CuO (R = Nd, Sm, Gd, Tm) systems;phase relations;Ca10R4Cu24O41 (R = Nd, Sm, Gd) structure;Ca2+xR2-xCu5O10 (R = Nd, Sm,;Gd, Tm) structure;ternary-system;approximately 950-degrees-c;high-pressure;superconductivity;diagram;air;er;compatibilities;property;oxide
Journal of Magnetism and Magnetic Materials
Measuring the temperature dependence of the ac-initial susceptibility chi-ac (T) of Nd2Fe14B, two peaks were found. One peak, which is at 140 K, corresponds to the occurrence of the spin reorientation transition. The second one, which is at 220 K, can be correlated to the temperature where the FOMP (first order magnetization process) transition starts. A similar behaviour was found in Nd2Fe14C and Nd2Co14B also. Only one peak was detected for Pr2Fe14B and Pr2Co14B, suggesting that no spin reorientation but a FOMP does exist in these compounds. Direct measurements of the temperature dependence of the critical FOMP field and the anisotropy field using the SPD technique prove that this peak occurs due to the FOMP transition. A theoretical, however phenomenologically based, analysis gives an explanation for the occurrence of these peaks in chi-ac (T). Furthermore, it can be shown that the peak in the ac-initial susceptibility, which indicates the onset temperature of the FOMP, can be detected only by measuring either on polycrystalline samples or applying the external ac-field in some special crystallographic directions of a single crystalline sample. The peak which corresponds to the occurrence of a FOMP will disappear if the external ac-field is applied parallel to the c-axis or preferential axis of a magnetically oriented sample. This gives an opportunity to differentiate a peak due to a FOMP from that of a spin reorientation by ac-initial susceptibility measurements. It should be mentioned that this new and simple method gives the possibility to get direct information whether there exists a FOMP transition in a compound or not. This is especially important if a FOMP occurs at very high fields which are far beyond the limit of the current facilities. This allows also the experimental test of CEF calculations which predict sometimes a FOMP transition in high magnetic fields and the critical temperature range where high order CEF terms can or cannot be neglected.
关键词:
high-field magnetization;single-crystal nd2fe14b;anisotropy;r2fe14b;y2fe14b;dependence;exchange;pr2fe14b;r2co14b;alloys
