高等学校化学学报

高等学校化学学报 ›› 2001, Vol. 22 ›› Issue (3): 349.

• 研究论文 •    下一篇

EXAFS研究Ni-B和Ni-Ce-B超细非晶态合金的退火晶化

王晓光1, 闫文胜1, 钟文杰1, 张新夷1, 韦世强1,2   

  1. 1. 中国科学技术大学国家同步辐射实验室, 合肥 230029;
    2. 中国科学技术大学天文与应用物理系, 合肥 230026
  • 收稿日期:2000-04-11 出版日期:2001-03-24 发布日期:2001-03-24
  • 通讯作者: 韦世强(1962年出生),男,博士,教授,博士生导师,主要从事同步辐射技术的建设及其应用、凝聚态物理和表面催化的研究.E-mail:sqwei@ustc.edu.cn E-mail:sqwei@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(批准号:29673038);中国科学院“百人计划”资助

Annealed Crystallization of Ni-B and Ni-Ce-B Ultrafine Amorphous Alloys Studied by EXAFS

WANG Xiao-Guang1, YAN Wen-Sheng1, ZHONG Wen-Jie1, ZHANG Xin-Yi1, WEI Shi-Qiang1,2   

  1. 1. National Synchrotron Radiation Laboratory, University of Scienceand Technologyof China, Hefei 230029, China;
    2. Department of Astronomyand Applied Physics, Department of Physics, Universityof Scienceand Technology of China, Hefei 230026, China
  • Received:2000-04-11 Online:2001-03-24 Published:2001-03-24

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被引次数

35

摘要： 采用同步辐射EXAFS技术定量地研究化学还原法制备的Ni-B和Ni-Ce-B超细非晶态合金中Ni原子的局域环境结构随退火温度升高而产生的变化.结果表明,对于Ni-B和Ni-Ce-B超细非晶态合金初始样品:Ni-Ni最邻近配位壳层的平均键长RNi—Ni、配位数N、热无序σT、结构无序σS分别为0.275nm,11.9,0.0069nm,0.034nm;0.276nm,12.4,0.0067nm,0.035nm.Ni-B最邻近配位壳层的RNi—B,N,σT,σS分别为0.215nm,2.7,0.0055nm,0.0038nm;0.214nm,2.9,0.0058nm,0.0042nm.Ni—Ni配位的σS很大,是其σT的4～5倍,比Ni-B配位的σS大近一个数量级.在300℃退火后,Ni-B样品开始发生晶化生成晶态Ni3B,其RNi—Ni和σS分别为0.254nm和0.011nm,σS降低近2倍;而0.3%原子比的Ce掺入后使Ni-Ce-B超细非晶态合金的晶化温度升高100℃左右.在500℃退火后,Ni-B样品的结构参数与Ni箔的相近,但Ni-Ce-B样品的Ni-Ni配位的σS仍为0.0073nm,Ni-B配位的N为1.2,表明稀土元素Ce(以CeO2存在)显著增强了Ni与B的相互作用,且同时使退火晶化生成的Ni晶格结构产生畸变.

关键词: EXAFS, Ni-B, Ni-Ce-B, 超细非晶态合金

Abstract: EXAFS technique was used to quantitatively determine the local structure evolutions of Ni-B and Ni-Ce-Bultrafine amorphous alloys prepared by chemical reduction during the annealed process. The results show that the average bond length Rj, coordination number N, thermal disorder factor σTand static disorder factor σSare 0.275 nm, 11.9, 0.0069 nm, 0.034 nm; 0.215 nm, 2.7, 0.0055 nm, 0.0038 nm, and 0.276 nm, 12.4, 0.0067 nm, 0.035 nm; 0.214 nm, 2.9, 0.0058 nm, 0.0042 nm for the Ni-Ni and Ni-Bfirst neighbor shells of Ni-Band Ni-Ce-Bultrafine amorphous alloys, respectively. It is indicated that the σSof Ni-Ni shell is rather larger, about four or five times as large as that of σT, and one order larger than that of σSof Ni-Bshell. Ni-Bsample is crystallized after being annealed at 300 ℃, and its RNi—Ni as well as σSare 0.254 nm and 0.011 nm, respectively. However, the crystallization temperature of Ni-Ce-Bsample increases about 100 ℃ due to the addition of 0.3% Ce element. The local structure around Ni atom for the Ni-Bsample annealed at 500 ℃ is fully similar to that of Ni foil. For the Ni-Ce-Bsamples annealed at 500 ℃, the σSof Ni-Ni shell is 0.0073 nm and the N of Ni-Bshell is 1.2. It implies that the Ni lattice produced from the crystallization of Ni-Ce-Bamorphous alloys is significantly distorted and the interaction between Ni and Batoms is strongly increased by the effect of Ce element.

Key words: EXAFS, Ni-B, Ni-Ce-B, Ultrafine amorphous alloy

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