杨中正
,
姚亚刚
,
WONG C P
,
陆跃军
材料工程
doi:10.11868/j.issn.1001-4381.2015.06.005
以硝酸铝和硅溶胶为原料,采用微沸法对合成纳米莫来石及其活化能进行研究,并用热重差示扫描热量计(TGDSC)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成莫来石的粒度、相组成和形貌进行分析.结果表明:在原料中的铝硅摩尔比为3∶1的条件下,温度为854℃时莫来石开始形成,温度为920℃时Al Si尖晶石开始转变为莫来石,温度为1200℃时莫来石化完成,合成莫来石的活化能为(634.52±28.90)kJ·mol-1.经过1200℃煅烧后,莫来石含Al2O3的摩尔分数为59.8％,平均粒度约为31.7nm,形状为针状,并由这些针状莫来石构成连续的网络结构.随着铝硅摩尔比的增加,合成莫来石的温度降低,活化能降低.当铝硅摩尔比增加至6∶1,合成莫来石的活化能降至(514.73±14.40)kJ·mol-1.
关键词:
微沸法
,
纳米莫来石
,
活化能
段宝玉
,
刘宗昌
,
任慧平
,
霍文霞
兵器材料科学与工程
研究P91、P92钢的过冷奥氏体转变具有重要理论意义和工程应用价值.汇总了P91、P92钢的CCT图和TTT图,对这些C-曲线进行分析和评价,指出存在的缺点,展示了P92钢的新的TTT图.P92钢的等温转变组织形貌较为特殊:珠光体组织为纤维状,下贝氏体呈颗粒状.
关键词:
P91钢
,
P92钢
,
CCT图
,
TTT图
,
珠光体
,
贝氏体
Journal of Materials Research
In this article, we describe oxidation of molten Sn-0.07 wt% P alloy exposed in air at 280 degrees C. Although oxidation can be effectively reduced by the addition of trace phosphorus, the oxide film has a poor protection for the molten alloy with a high P concentration. The oxide film was analyzed by x-ray photoelectron spectroscopy. Comparing the results with the low P sample, there was a high phosphorous content in the film and a new Sn-P compound on the surface of the high P sample. It is assumed that the poor protection against oxidation of the film could be due to volatility of phosphorus in the Sn-P alloy at the temperature.
关键词:
sn
Optical Materials
The electronic structures of C, C-Al and C-Ga doped ZnO were investigated from the first-principles based on density functional theory (DFT). It was found that the C-doped ZnO where 1/8 Os are substituted by C is p-type with hole carriers locating nearby valence band maximum. Moreover, the Madelung energy increases in this case. Incorporating the reactive donor Al or Ga into C-doped ZnO system at Zn sites, not only enhances the C acceptor concentration, but also gets a shallower C acceptor energy level in the band gap in p-type codoped ZnO crystals and decreases the Madelung energy. (c) 2009 Elsevier B.V. All rights reserved.
关键词:
Codoping;First-principles;ZnO;Electronic structures;zno
郭忠诚
,
陈凌
,
杨显万
,
翟大成
电镀与涂饰
doi:10.3969/j.issn.1004-227X.2000.03.001
研究了RE-Ni-W-P-B4C-PTFE复合镀层的性能.结果表明:热处理温度对RE-Ni-W-P-B4C-PTFE复合镀层的硬度影响很大,当温度达到400℃时,复合镀层的硬度达到极大值(1145 Hv);在同一热处理温度下,当保温时间达到3小时,镀层的硬度值最佳.当热处理温度达到300℃时,RE-Ni-W-P-B4C-PTFE复合镀层的耐磨性最好.高温氧化试验表明:RE-Ni-W-P-B4C-PTFE复合镀层随氧化时间和温度的延长,被氧化的程度增加.
关键词:
电沉积
,
RE-Ni-W-P-B4C-PTFE复合镀层
,
性能
Y.F. Gao
,
J.Tan
,
G.D. Liu
,
C.L.Zhang
,
T.Liuand R.Z Ma (Rapidly Quenched Materials Research and Development Centre
,
Central Iron & Steel Research Institute
,
Beijing 100081
,
China)(Metal Physics Department
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
A mostly single bcc phase with grain sizes of 15-20 nm was prepared by crystallization of amorphous Fe-P-C-Mo-Cu-Si alloys.The Bs value (H=10000 Oe) reaches 1.595 T for Fe(79.5) P(12)C6Cu(0.5)Mo(0.5)Si(1.5) alloys. The low core loss of 0.14 w/kg at 1.3 T and 50 Hz was confirmed for the bcc Fe(79.5)P(12)C6Cu(0.5)Mo(0.5)Si(1.5) alloy.The structures of the alloy annealed at different temperatures have been investigated by means of Xray diffraction and transmission electron microscope. The relationship between the structure and magnetic properties of the alloy is discussed.
关键词:
: amorphous alloy
,
null
,
null
