共查询到18条相似文献,搜索用时 62 毫秒
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在0.6!keV Ar+高剂量(~1022/cm2)辐照石墨表面,借助于高分辨透射电子显微镜(HRTEM),发现有六方金刚石纳米晶产生.它们的平均直径介于1-50!nm之间,而且晶粒个数约随其直径的增大而直线减少.有趣的是,晶粒具有两种结构模式:直径小于10!nm的晶粒为单晶结构,而直径大于10!nm的为多晶结构.基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点,讨论了这种双重结构的形成性质. 相似文献
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在0.6keV Ar+高剂量(~1022/cm2)辐照石墨表面,借助于高分辨透射电子显微镜(HRTEM),发现有六方金刚石纳米晶产生.它们的平均直径介于1—50nm之间,而且晶粒个数约随其直径的增大而直线减少.有趣的是,晶粒具有两种结构模式:直径小于10nm的晶粒为单晶结构,而直径大于10nm的为多晶结构.基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点,讨论了这种双重结构的形成性质.
关键词:
离子轰击
六方金刚石纳米晶 相似文献
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应用原位能量色散X射线散射和金刚石对顶砧技术,对纳米晶ZnS进行了高压结构相变研究。初始相为纤锌矿结构的10 nm和3 nm硫化锌分别在16.0 GPa和16.7 GPa时转变为岩盐矿结构,相变压力均高于纤锌矿结构的体材料硫化锌。该相变为一可逆的结构相变。应用大型科学计算软件Materials Studio(MS)计算了纳米晶ZnS的状态方程,根据Birch-Murnaghan方程拟合了纳米晶ZnS的零压体模量,得到的零压体模量高于相应体材料的零压体模量,表明纳米晶ZnS较难压缩。 相似文献
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研究了蚀刻气体对生长在硅衬底上纳米晶金刚石合成的影响.合成方法为热丝化学气相沉积法,衬底温度为550 oC,反应压力为4 kPa. 其中甲烷和氢气分别作为源气体和稀释气体. 氮气、氢气和氨气用作蚀刻气体. 结果表明,仅氢气作为蚀刻气体可获得最佳工艺条件. 相似文献
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O. N. Breusov G. A. Abrosimova A. V. Ananiin A. S. Aronin V. N. Drobyshev V. F. Tatsii 《高压研究》2013,33(3):191-197
Abstract The diamond-like amorphous carbon phase was obtained by means of detonation compression of mixtures of an explosive with soot or graphite. The pycnometric density of powders after compression and treatment in boiling acids achieved 3.42 g/cm3. The X-ray and TEM study showed that fine-grained crystalline and nanocrystalline diamond was also present in the samples in addition to the diamond-like amorphous phase. 相似文献
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M. Tanemura T. Okita J. Tanaka H. Yamauchi L. Miao S. Tanemura R. Morishima 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,34(1-3):283-286
Glassy carbon plates, a Ni mesh coated with a carbon film and mechanically
polished graphite plates were Ar+ ion-bombarded with and without a
simultaneous Mo supply at room temperature. Conical protrusions were formed
on the sputtered surfaces, and in some cases carbon nanofibers (CNFs) 0.2–10 μm in length and 10–50 nm in diameter grew on the tips. The growth of CNF-tipped-cones was optimized in terms of the ion-incidence angle and the rate-ratio of sputtering and seeding. Oblique sputtering was proved to
be quite effective to grow the CNF-tipped-cones. Thus, the redeposited massive carbon atoms onto cones were thought to diffuse toward the cone tips, resulting in CNF formation. This growth mechanism was confirmed by transmission electron microscope (TEM) observation disclosing the
boundary-less structure between conical bases and CNFs. TEM observation of
CNF-tipped-cones also revealed no-hollow structure and an amorphous nature
of CNFs. Since this sputtering method is a room-temperature process and
quite straightforward, ion-induced CNFs promise to have myriad applications,
such as field emission sources for flat panel displays. 相似文献
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C. Popov W. Kulisch S. Bliznakov B. Mednikarov G. Spasov J. Pirov M. Jelinek T. Kocourek J. Zemek 《Applied Physics A: Materials Science & Processing》2007,89(1):209-212
Thin nanocrystalline diamond/amorphous carbon (NCD/a-C) composite films and amorphous diamond-like carbon (DLC) films were
prepared by three methods: microwave plasma chemical vapour deposition (MWCVD) from methane/nitrogen mixtures (NCD/a-C), RF
magnetron sputtering of a pure graphite target in argon/methane ambients, and pulsed laser deposition (PLD) in vacuum or argon
atmosphere (DLC). The films prepared by the three techniques were comprehensively characterized with respect to their bonding
structure by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
PACS 81.05.Uw; 82.80.Pv 相似文献
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Diamond formation in hydrogenated amorphous-carbon films containing ultradisperse copper has been studied by measuring IR
absorption at two-phonon diamond frequencies. The anomalously high two-phonon absorption observed in the experiments has permitted
improving the sensitivity of the method. Mechanisms of the two-phonon absorption enhancement are discussed in terms of the
theory of a medium containing nanosized copper-doped graphite fragments. It is shown that the observed enhancement of two-phonon
absorption is caused by electrical induction of the local fields induced by irradiation in diamond nanocrystals acting on
adjoining copper-doped graphite fragments.
Fiz. Tverd. Tela (St. Petersburg) 41, 1863–1866 (October 1999) 相似文献
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Ar+ induced Auger electrons from Si and Ar were investigated at bombardment energies between 3–15 keV and target currents of
a few μA. The Auger electron yields were compared with secondary ion yields of Si and Ar by simultaneous SIMS-AES measurements.
In the ion induced Auger spectra of Si five Auger peaks and in the Ar spectra three Auger peaks were observed. The ion induced
Auger electron yield of Si and Ar were found to be strongly dependent upon the primary ion energy. “Bulk like” and “atomic
like” Auger transitions of ion induced Auger electrons of Si were observed. 相似文献
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The effect of the implantation of 150 keV Ar+ ions at different doses on the surface of amorphous Fe40Ni40B20 and the changes in the bulk properties following proton irradiations are investigated by conversion electron and transmission Mössbauer spectroscopy respectively. In the former case a correlation between the total Mössbauer absorption and the total energy deposited by incident Ar+ ions is established, indicating the development of certain stresses in the material, affecting the inter and intra molecular bonding in the near surface region. On the other hand, the proton irradiation seems to cause a reorientation of the atomic spins and also the formation of an additional Fe or Fe?Ni rich phase in the sample. Also the low field A.C. susceptibility is found to decrease as a function of the dose of incident protons. Possible reasons for the above behaviour are discussed. 相似文献
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R. T. Malkhasyan R. V. Arutyunyan L. V. Kamaeva E. I. Salamatov 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2014,49(1):34-38
We study thermal-physical characteristics of nano-sized amorphous tungsten and of its oxide. It is shown that a nano-size amorphous metal gets into a nano-size crystalline state after heating up to temperatures much lower than the half-temperature of melting, which is typical for all nano-size amorphous materials. Phase transition of amorphous nano-size WO2 into crystalline state occurs in the temperature range 350–520°C, while the same transition in case of W takes place in the range 1000–1370°C. The energy released at crystallization of nano-size amorphous metal amounts to 170±25 J/g coinciding practically with the value of specific melting heat of usual tungsten. Such a high additional energy of nano-size amorphous metals above the energy of nano-size crystalline metals is their main peculiarity which widens essentially the range of their practical applications. 相似文献