材料期刊网

T6态SiCp/A356高温干滑动摩擦磨损特性研究

金云学 , 王小丫 , 童强强 , Jung-Moo Lee

稀有金属材料与工程

采用T6态的SiCp/A356复合材料,以Al2O3陶瓷球作为对磨材料,借助UMT-2摩擦磨损实验机详细研究了复合材料的高温摩擦磨损性能,并采用SEM、OLS4000等手段分析材料的高温摩擦磨损特性.结果表明:T6态的SiCp/A356复合材料的磨损率随着温度的增加而增加.当温度低于150℃时,磨损率随温度缓慢增加;继续升高温度,磨损率进入稳定阶段,稳定磨损率为3.18×10-5 mg·cm1;当温度达到250℃时,磨损率呈线性上升.摩擦系数则随温度在0.40～0.45很小范围内波动,表现出优异的高温摩擦性能.同时,磨损机制由氧化磨损、磨粒磨损和疲劳磨损转变为严重的粘着磨损.

关键词: SiCp/A356 , T6热处理 , 高温 , 滑动摩擦磨损 , 磨损机制

EPR parameters and impurity structures for Cr3+ ions in KSC(MoO4)2, RbIn(MoO4)(2) and RbSC(MoO4)(2) crystals

Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The calculations of EPR parameters (g factors g(parallel to), g(perpendicular to) and zero-field splitting D) related to the impurity structures have been made from the high-order perturbation formulas for Cr3+ ions in trigonal KSc(MoO4)(2), RbSc(MoO4)(2) and RbSc(MoO4)(2) crystals. It is found that the MO6 octahedra in these crystals change from the trigonal elongation in the pure crystals to the trigonal compression in the impurity centers. The results are discussed. (c) 2004 Elsevier B.V. All rights reserved.

关键词: local lattice distortion;electron paramagnetic resonance (EPR);crystal;and ligand-field theory;Cr3+;KSc(MoO4)(2);RbIn(MoO4)(2);RbSC(MoO4)(2);electron-paramagnetic resonance;superposition-model analysis;phase-transitions;double molybdates;tungstates;pressure;centers;spectra;distortions;hosts

The thermoelectric power of charge-density-wave conductors Rb0.3MoO3 and Rb0.15K0.15MoO3

Solid State Communications

The thermoelectric power (TEP) of the quasi-one-dimensional charge-density-wave (CDW) conductors rubidium blue bronze Rb0.3MoO3 and its alloy Rb0.15K0.15MoO3 were measured in the temperature range 80-280 K. The result showed a sign change from a small positive value to a great negative value where the Peierls transition temperatures (T-p) are 183 and 180 K for Rb0.3MoO3 and Rb0.15K0.15MoO3, respectively. Above T-p, the TEP for both samples can be described with the empirical relation S=AT+B; while below T-p, the TEP fits well the relation S=AT+B/T based on the experimental data. The Fermi energies epsilon(F) for Rb0.3MoO3 and Rb0.15K0.15MoO3 are estimated to be 1.55 and 0.53 eV, respectively. (C) 2004 Elsevier Ltd. All rights reserved.

关键词: blue bronze;charge-density-wave;thermoelectric power;blue bronze k0.3moo3;thermopower;scattering;transport;phase

KPO_3-MoO_3熔盐相图

方建慧 , 唐赟 , 李郁 , 阎立诚 , 陈念贻 , 王继扬

金属学报

用目测变温法及差热分析法测定了KPO3－MoO3体系熔盐相图，发现该体系生成两个化合物，它们的化学计量式分别为3KPO3·MoO3和KPO3·MoO3，经X射线衍射及Raman光谱分析得到进一步证实。

关键词: KPO_3－MoO_3 , phase diagram , Raman spectrum analysis

Structure and surface characterization of alpha-MoO3 whiskers synthesized by an oxidation process

Scripta Materialia

alpha-MoO3 whiskers were prepared via an oxidation process of a Mo slice in oxygen. MoO3 vapors condensed to form the alpha-MoO3 whiskers with white color. On surfaces of the MoO3 whiskers, the atom ratio of oxygen to molybdenum was 4.4, which was higher than that of bulk MoO3. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

关键词: crystal growth;physical vapor deposition;crystal structure;crystalline oxides;molybdenum trioxide;oxygen sites;cluster;moo3

Co-MoO3纳米带的制备与表征

嵇天浩 , 杨逸雄 , 杜海燕 , 孙家跃

功能材料

采用水热离子交换法,以CoCl2和钼蓝H2MoO3纳米带为前驱物制备了含Co2+的正交相MoO3纳米带.测试结果表明,在Co2+掺入MoO3层间后基本没有改变前驱物纳米带的晶相和形貌;由Co2+掺入前后FTIR和XRD谱图的对比中还可证实,存在在钼蓝层间的H+不仅与[MoO6] 八面体中的端氧有较强的相互作用,而且还产生了新的晶面.

关键词: Co-MoO3纳米带 , 离子交换 , 水热合成

Single crystal T(0.3)MoO(3) growth by electrolytic reduction method of a T1(2)CO(3)-MoO(3) melts

Journal of Crystal Growth

Single crystals of quasi-one-dimensional charge-density-wave conductor blue bronze Tl(0.3)MoO(3) have been grown by electrolytic reduction method using the raw materials Tl(2)CO(3)-MoO(3) with composition around 1:4.3 mol ration. The electrolytic temperature was about 570 degrees C, and electrolytic current was 25 mA during the electrolytic process. By this method, the Tl(0.3)MoO(3) single crystals obtained have a relatively large average size and high quality. Platelet crystals with typical dimensions of 7 x 2 x 1 mm(3) were obtained. The crystal structure is monoclinic with space group C2/m. The parameters of the unit cell of the single crystal are as follows: a = 18.486(6)angstrom, b = 7.555(2)angstrom, c = 10.032(3)angstrom and beta = 118.38(3)degrees. The C-center symmetry of Tl(0.3)MoO(3) crystal is demonstrated by the selected area electron diffraction (SAED) patterns in the transmission electron microscope (TEM). The full-width at half-maximum (FWHM) of the rocking curve of the (201) Bragg peak of the Tl(0.3)MoO(3) was approximately 0.4 degrees. These are evidences that the single crystal is of high quality. The temperature dependence of the resistivity shows that a metal-semiconductor transition occurs near 181 K. (c) 2005 Elsevier B.V. All rights reserved.

关键词: electrolytic reduction;single crystal growth;thallium blue bronze;Tl(0).(3)MoO(3);charge density wave;charge-density-wave;molybdenum oxide bronzes;blue bronze;nonlinear;transport;k0.3moo3;k0.30moo3;memory;dynamics;lithium;noise

抑制MoO3高温挥发的试验研究

杨柳 , 肖君臣 , 宋志宇 , 刘双 , 宋生强 , 薛正良

钢铁研究

试验研究了温度和添加剂对MoO3挥发的影响。结果表明，温度越高，MoO3挥发越激烈，1600℃时挥发率达N13．22％。当添加CaO时，MoO4挥发率降低，1600℃下当w（CaO）达N20％～30％时，M003的挥发率降低到2％左右。XRD分析结果表明，CaO与M003生成了CaMoO4，从而降低了MoOa的活性，因此添加CaO能有效抑制MoOs的挥发。

关键词: MoO3挥发 , 直接合金化 , CaO

MoO3对染料光催化降解性能研究

邓凡政 , 梁娟妮 , 戈霞

稀有金属 doi:10.3969/j.issn.0258-7076.2004.06.017

分别在太阳光、红外灯光、荧光灯光不同光源照射下,用仲钼酸铵硝酸分解法和热分解法制备MoO3,对几种常见染料光催化降解性能进行了研究.研究了溶液的酸度、催化剂的用量、光照时间等不同条件对染料脱色率的影响.结果表明,用仲钼酸铵硝酸分解法制备的MoO3在酚藏花红、罗丹明B、甲基紫等染料的光催化降解过程中催化活性好,脱色率可达90%以上;将使用过的MoO3重复实验,其光催化活性基本不变,性能稳定,可重复使用;加入Fe3+,H2O2等其他物质可提高染料的脱色率;对染料原溶液和脱色后的溶液进行紫外-可见光谱分析,发现染料脱色确实由光催化降解所致.

关键词: 三氧化钼 , 染料 , 光催化降解 , 脱色率

Local structure and EPR g factors for KA1(MoO4)(2): Cr3+ and RbIn(MoO4)(2): Cr3+ systems

Journal of Alloys and Compounds

For a d(3) configuration ion, the 120 x 120 complete energy matrix which contains the electron-electron repulsion interaction, the ligand field interaction, the spin-orbit coupling interaction as well as the Zeeman interaction, has been established. By diagonalizing the complete energy matrix, local structure and EPR g factors for Cr3+ ions doped in KA1(MoO4)(2) and RbIn(MoO4)(2) have been investigated, respectively. It is found that the orbit reduction effect is very important to understand the EPR g factors for Cr3+ ions doped in KA1(MoO4)(2) and RbIn(MoO4)(2), and some characteristics of orbit reduction on the EPR g factors are discussed firstly. Simultaneously, by simulating the calculated optical spectra and the EPR spectra data to the experimental results, we obtain the local structure parameters R = 2.043 angstrom, theta = 53.5940 degrees and R = 2.065 angstrom, theta = 56.0434 degrees for Cr3+ ions doped in KA1(MoO4)(2) and RbIn(MoO4)(2), respectively. The calculated results show the local lattice structure of the octahedral Cr3+ centers in KA1(MoO4)(2) and RbIn(MoO4)(2) exhibit an elongation and a compression distortions, respectively. (c) 2006 Elsevier B.V. All rights reserved.

关键词: local structure;orbit reduction effect;KA1(MoO4)(2): Cr3+ and;RbIn(MoO4)(2): Cr3+ systems;EPR g factors;electron-paramagnetic resonance;phase-transitions;spectroscopic;properties;kal(moo4)(2) crystal;optical-properties;cr3+;tungstates;parameters;centers;spectra