D.Eylon
,
S.R.Seagle
材料科学技术（英文）
The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.
关键词:
TG.Nieh(Lawrence Livermore National Laboratory
,
P.O.Box 808
,
L-350
,
Livermore
,
CA 94551
,
USA )
材料科学技术（英文）
Intermetallic beryllides are potential light-weight, high-temperature structural materials. In this paper. the processing techniques, microstructure. deformation, and oxidation properties of intermetallic beryllides are described. In addition to nickel beryllides (NiBe). which is treated as a model system.other high beryllium-containing refractory beryllides, such as Nb2 Be17. VBe12. are also studied.The room temperature deformation and high-temperature creep properties of these beryllides are repor4ed. At room temperature. NiBe exhibits certain tensile ductility (~ 1 .3%). but all other beryllides are essentially brittle. Nonetheless, these beryllides become ductile at temperatures above approximately 1000℃. Their creep properties are presented. The creep properties are compared with those of intermetallic aluminides. Also. a comparison is made between the ductile-to-brittle transition behaviour of intermetallic beryllides and that of aluminides. Although beryllides are generally oxidation resistant at high temperatures, some beryllides, e.g., ZrBe13, suffer the pest reaction during oxidation at intermediate tem peratures. The pest mechanisms are proposed
关键词:
Corrosion Reviews
The corrosion field experienced a rapid growth in knowledge and innovations in the last decade. In this paper, a bibliometric analysis was applied to evaluate the global scientific production of corrosion papers (46,384 pieces) front 1992 to 2007 in all journals of all the subject categories of the Science Citation Index Expanded (SCIE) compiled by the Institute for Scientific Information (ISI), Philadelphia, USA. The analysis of the published Outputs showed that research on corrosion increased steadily over the past 16 years and the researchers from the EU, the USA and China contributed greatly to the rise in publications. Synthetically analyzing the information including international cooperation, subject category, distribution Of journals, document type, document language and author keywords, the development of corrosion research over the past 16 years has been visualized and several key findings were provided. This bibliometric method can help relevant researchers realize the panorama of global corrosion research, and establish the further research direction.
关键词:
Corrosion;Bibliometrics;Research trends
Journal of Solid State Chemistry
A new compound, beta-SrGaBO4, has been attained through solid phase transition from alpha-SrGaBO4 at high temperatures. Its crystal structure has been determined from powder X-ray diffraction data by direct methods. The refinement was carried out using the Rietveld method and the final refinement converged with Rp = 11.42 % and Rwp = 15.16 %. It has an orthorhombic P2(1)2(1)2 space group with cell parameters a = 15.3706(2) Angstrom b = 8.992 1 (1) Angstrom, c = 5.919 1 (1) A, and Z = 8. The structure of beta-SrGaBO4 is built up from Ga2BO8 units formed by two GaO4 tetrahedra and one BO3 triangle, and Sr2O12 units formed by two SrO7 groups. Tetrahedra [GaO4] are linked by shared O(3) and O(7) atoms to form infinite chains along the e axis. (C) 2002 Elsevier Science, (USA).
关键词:
beta-SrGaBO4;borate;structure determination;X-ray powder diffraction;crystal-structure
Composites Science and Technology
The thermal expansion of the reference sample, pure copper film in the temperature range of - 120 to 200 degrees C was first measured using the newly improved CCD imaging technique for measurement of thermal expansion of thin films. The results showed good accordance with the recommended data given by TPRC (Thermophysical Properties Research Centre, USA) handbook, verifying that the present method is valid for measuring thermal expansion of films. Then, the thermal expansion TE (Delta L/L-0) of silica/polyimide composite films with different SiO2 fractions i.e. 0, 1, 3, 5, 8, 10 and 15 wt% prepared using the sol-gel technique was obtained in the temperature range of - 120 to 200 degrees C using the newly improved CCD method and the differential coefficient thermal expansion (CTE) can be deduced by Delta L/L-0 similar to temperature relation. The CTE Of SiO2/PI Composite films decreased with the increase Of SiO2 content and the decrease of temperature. An empirical equation of CTE of SiO2/PI with SiO2, content has been given in this paper. (C) 2007 Elsevier Ltd. All rights reserved.
关键词:
silica/polyimide composite film;thermal expansion;CCD imaging;technique;low temperature;elevated temperature;mechanical-properties;cryogenic properties;nanocomposite films;polyimide films;low-temperature;silica
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
陈猛
,
吴也凡
,
石纪军
,
何汝杰
,
赵学国
,
韦斐
,
罗凌虹
硅酸盐通报
以粉煤灰、固体燃料以及少量黏结剂为主要原料,采用KAl(SO4)2·12H2O和碱性激发剂作为Al2O3的前驱体,通过溶胶-凝胶法对粉煤灰粉体进行表面包覆改性,在原灰表面形成无定型态Al(OH)3溶胶提高了原粉煤灰的表面活性,由于降低了原灰颗粒的表面能,从而降低了样品烧结温度.借助Zeta电位分析仪(Brookhaven Instruments Corp,USA)分析粉煤灰改性前后表面所带电荷(ξ电位)随pH值变化情况,确定了改性处理化学反应体系最佳pH范围是7.8～8.1;探讨了制备工艺对改性后粉煤灰颗粒表面ξ电位和分散体系性能的影响.借助TGA-DSC分析和XRD分析研究了粉体热处理过程中的相变化,确定了改性粉煤预处理制度以及粉煤灰制备样品的热处理制度.
关键词:
KAl(SO4)2·12H2O(明矾)
,
溶胶-凝胶
,
工艺
