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1.
铈在Fe-28Al合金中的作用   总被引:3,自引:0,他引:3  
以稀土元素Ce为微合金化元素,研究了Ce对Fe3Al二元合金(Fe28Al)室温力学性能的影响,采用光学显微镜、扫描电镜、透射电镜、X射线光电子能谱仪、等离子耦合光谱、X射线衍射仪以及俄歇能谱仪等现代微观分析手段,探讨了Ce微合金化对Fe3Al合金组织结构和力学性能影响的作用机制。研究结果表明,Ce的加入改善了合金的室温塑性和强度,并在合金中起到了脱硫、脱氧、改变夹杂物形态、细化晶粒以及表面改性等作用。此外还对富Ce相颗粒在合金中的形态分布作了分析。  相似文献   

2.
稀土对ZA-27合金高温性能的影响   总被引:18,自引:2,他引:16  
研究了cCe≥45%(wt)的混合稀土对ZA-27合金显微组织及高温机械性能的影响。结果表明,在锌铝合金中,稀土元素可与Al、Zn、Cu等形成多种复杂成分化合物,其硬度高,热硬性好,分散于晶界或枝晶间,细化了组织,且有效地阻碍了高温时基体的变形和晶界移动。添加适量的稀土,可使ZA-27合金在150℃时的抗拉强度提高30%,硬度提高25%,延伸率虽有所下降,但冲击韧性却得以改善。同时发现,室温强度变化不大,唯塑性、韧性略有下降。  相似文献   

3.
本文用茜素S作萃取剂,研究了Fe,Co,Ni,Cu,Zn,Cd,Al在聚乙二醇-硫酸铵-茜素S体系中的非有机溶剂萃取行为。实验结果表明,在pH5的HAc-NaAc缓冲溶液中,Fe,Al与茜素S的络合物可被PEG相几乎完全萃取,Cu,Ni部分被萃取,而Co,Zn,Cd则不被萃取,从而实现了Fe与Co,Zn,Cd及Al与Co,Zn,Cd混合离子间的定量分离。  相似文献   

4.
影响TiAl合金塑性的电子结构因素   总被引:2,自引:0,他引:2  
应用EHT紧束缚能带计算方法, 系统研究了Ti-48Al-2M 为模型的γ-TiAl掺杂合金的电子结构。发现能有效地改善合金塑性的元素V、Cr、Mn 主要在两方面改变了γ-TiAl合金的电子结构,即改善Ti周围成键强度的各向均衡性和改变Ti、Al参与成键的电子分布,使成键电子云的球形化成分增大。研究结果表明V、Cr、Mn 等取代Al时成键的均衡性及电子云球形化均增大,从而有利于材料变形改善塑性,而加入Fe、Co、Ni虽然改善电子云的球形化但却不利于成键强度的均衡性,因而对合金的塑性无明显改善。  相似文献   

5.
甲醇催化氧化重整反应制氢的研究   总被引:14,自引:1,他引:13  
陈兵  董新法 《分子催化》2000,14(3):205-208
研究了Cu/Zn/Al系列催化剂催化甲醇氧化重整反应制氢,得到活性,选择性及稳定性较好的催化剂Cu60Zn30Al5Ce5;并且考察了Cu60Zn30Al5Ce5为催化剂时,该反应的工艺条件如温度,物料配比等,当压力为0.1MPa,温度为240℃,CH3OH:H2O=1:0.8,CH3OH:O2=4:1时,甲醇的转化率达97.75%,在此反应条件下,反应100h后,甲醇的转化率仍在96%以上。  相似文献   

6.
侯列奇  王树安 《分析化学》1995,23(8):919-921
本法对U3Si中22个微量杂质元素的测定,进行了较系统的实验研究,取样100mg时,Al、Ca、Cd、Cr、Cu、Fe、Hf、In、Mg、Mn、Mo、Nb、Ni、Pb、Sn、Ta、Ti、V、Y、Zn和Zr的测定范围5μg/g-800μg/g,回收率为94%-105%,RSD(n=8)0.4%-1.2%。  相似文献   

7.
王淑英  潘利华 《分析化学》1993,21(12):1452-1454
本文研究了ICP-AES测定Mg-Nd合金样品中10种元素的分析方法。选择了同时测定合金中La、Ce、Pr、Sm、Fe、Al、Mo、Ni、Cu和高含量Nd(20%)的条件。得到了满意结果。  相似文献   

8.
利用穆斯堡尔谱和X射线和衍射研究了4种Al-Fe-V-Si-Mu合金的Fe的原子组态。结果表明,添加混合稀土元素后抑制了基体合金Al-Fe-V-Si中α-Al13(Fe,V)3Si弥散粒子相的析出;当稀土含量6at%时,形成了Al-Fe-V-Si-Mu非晶态,采用Voigt基函数作了穆斯堡尔谱的合理拟合和分析。  相似文献   

9.
ICP-AES 法测定 RZnAl5RE 合金中的镧、铈、铁、铝、铅、镉   总被引:3,自引:2,他引:1  
采用ICP-AES测定了RZnAl5RE合金中的La、Ce、F3、Al、Pb、CD元素含量。考察了基体及无机酸浓度对6种元素线强度的影响。选择了仪器工作条件,检出限在0.03~1.00μg/L之间,加标回收率为93%~108%,相对标准偏差小于12.68%(n=10)。  相似文献   

10.
氧化锆对铜基甲醇合成催化剂的促进作用(英文)   总被引:1,自引:0,他引:1  
采用离子掺杂价态补偿原理,在Cu-Zn-Al甲醇合成催化剂中添加适量氧化锆助剂研制Cu-Zn-Al-Zr催化剂的特性。实验结果表明,最佳反应温度为230℃,比Cu-Zn-Al约低10℃。采用XRD、UVDR、FTIR、TPD和TPR等谱学方法对2种催化剂进行表征显示,铜基催化剂的活性位可能是“Cu0-Cu+-O-Zn2/A2O3-ZrO2”,工作态Cu-Zn-Al-Zr催化剂表面上Cu/Cu0的比值、价态稳定性和对CO的吸附量均大于Cu-Zn-Al,这与该催化剂具有较好的低温活性和较高的热稳定性密切相关。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

19.
20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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