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1.
采用分子动力学方法和QSC(QuantumSutton Chen)力场研究了升温速率对金属银和金属铅的熔化和过热行为的影响。研究结果表明,升温速率对金属银和铅的熔化和过热行为有很大影响,随着升温速率的升高,金属的熔点有所升高。高的升温速率会导致金属体系内部无序化程度增加,降低了熔化相变的能垒。升温速率导致的银和铅完美晶体的过热极限分别为1450K和800K。 相似文献
2.
升温速率对金属熔化和过热的影响 总被引:1,自引:0,他引:1
采用分子动力学方法和QSC(Quantum Sutton-Chen)力场研究了升温速率对金属银和金属铅的熔化和过热行为的影响。研究结果表明,升温速率对金属银和铅的熔化和过热行为有很大影响,随着升温速率的升高,金属的熔点有所升高。高的升温速率会导致金属体系内部无序化程度增加,降低了熔化相变的能垒。升温速率导致的银和铅完美晶体的过热极限分别为1450K和800K。 相似文献
3.
To improve the properties of Sn10Sb8Cu solder alloy, two new solders(SnSbCuAg and SnSbCuNi)were formed by adding small amounts of Ag or Ni into the solder alloy. The results show that the melting point of the SnSbCuAg solder alloy decreases by 14.1℃ and the spreading area increases by 16.5% compared to the matrix solder.The melting point of the SnSbCuNi solder alloy decreases by 5.4℃ and the spreading area is slightly less than that of the matrix solder. Microstructure analysis shows that adding trace Ag makes the melting point decline due to the dispersed distribution of SnAg phase with low melting point. Adding trace Ni,Cu_6Sn_5 and (Cu,Ni)_6Sn_5 with polyhedron shape on the copper substrate can be easily seen in the SnSbCuNi solder alloy,which makes the viscosity of the melting solder increase and the spreading property of the solder decline. 相似文献
4.
采用沉淀法和光照还原沉淀法分别制备了Ag_3PO_4和Ag/AgCl/Ag_3PO_4两种可见光光催化剂,在可见光照射条件下,分别考察了其对水溶液中嗪草酮的降解动力学过程,并比较了二者的光催化活性差异以及稳定性.研究表明:嗪草酮的光催化降解过程均符合表观一级反应动力学,Ag/AgCl/Ag_3PO_4的催化活性和稳定性明显优于Ag_3PO_4,剂量为200 mg/L时,20 min内对嗪草酮的降解率达99%以上,循环使用4次后,降解率仍维持在88%以上. 相似文献
5.
姜雪梅 《沈阳理工大学学报》2007,26(3):50-52
针对冲击波加载实验中晶体的过热熔化现象,分析了静高压和冲击压缩后的样品的实验数据,给出了晶体发生过热熔化的充分条件.并采用分子动力学模拟的方法,验证了所得结论的正确性. 相似文献
6.
李洋 《武汉理工大学学报(材料科学英文版)》2017,32(3):568-573
Octahedral CoO with nanostructures decorated with Ag nanoparticles was prepared via a facile solvothermal approach. After being annealed at 500 °C for 1 h, an electrochemical capacitor material of Co3O4 decorated with Ag2O was obtained. The cyclic voltammetry and galvanostatic charge-discharge were used to evaluate the electrochemical properties of the as-prepared products. The results indicated that the as-prepared samples exhibited fine pseudo-capacitive performance, and the surface modifications of Ag2O can significantly increase the capacitance of the Co3O4 material. The specific capacitance of Ag2O/Co3O4 composite electrode was up to 217.6 F·g?1, which was 3.35 times as high as that of pure Co3O4. Moreover, Ag2O/Co3O4 composite showed an excellent cycle performance, and 65.3% of specific capacitance was maintained after 200 cycles. 相似文献
7.
利用差示扫描量热仪(DSC)对联苯的熔点、熔融焓、结晶焓进行测定,实验结果显示在不同升温/降温速率下DSC法对联苯的熔点的测定结果影响较大,而对熔融焓和结晶焓并无影响.测定联苯固体比定压热容(283.15~323.15K)、液体比定压热容(363.15~443.15K),并将比定压热容与温度进行关联,导出计算比定压热容的方程.同时介绍利用DSC测得联苯纯度的方法. 相似文献
8.
Silver nanoclusters (NCs) embedded in soda-lime glass was synthesized by the electric fieldassisted diffusion (EFAD) and successive annealing. The samples were characterized by UV-Vis absorption spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy (XPS), and lifetime measurements. The experimental results show that the growth of silver clusters is favored by the annealing temperature and dwell time. The as-diffused and annealed glass samples show photoluminescence around 550 nm under UV excitation, which can be associated with the presence of L-center and Ag3 + cluster. And the increasing of the annealing temperature and dwell time results in an appearance of the SPR peak and the decreasing of the luminescence intensities because the Ag3 + clusters grow up into the Ag nanoparticles. 相似文献
9.
Effects of the main process parameters(temperature and time) on microstructure and properties of Ti(C, N)/Ni interface bonded
by (Cu+Nb) interlayer in a vacuum diffusion bonding device were investigated. The interfacial microstructures consisted initially
of Ni3Nb metallic compound and eutectic of Ni3Nb+CuNiSS, and finally transformed to (Ti, Nb) (C, N)+Ni3Nb near Ti (C, N) and NiCuSS+Ni3Nb near Ni when diffusion bonding temperature was 1 523–1 573 K. It was clear that Cu was a constituent in the transient liquid
phase (TLP) into which Ni was dissolved by forming Cu-Ni transition liquid. Nb was dissolved in Cu-Ni transition liquid rapidly.
Ti (C, N) conld be wetted by resultant Ni-Nb-Cu transient liquid phase which was followed by a little (Ti, Nb) (C, N) solid
solution formed at interface. This increased the interface combining capability. Ultimately the interface shear strength was
able to reach 140 MPa. The theoretle analysis and experimental results show that the growth of interfacial reaction layer
Ni3Nb accords with parabola law, and the activation energy of diffusion reaction is 115.0±0.5 kJ/mol, while the diffusion reaction
speed constant is 12.53 mm/s1/2.
Funded by the National Natural Science Foundation of China (No. 50074017/E0408) 相似文献
10.
为提高Al18 B4O33 w/Al复合材料的室温阻尼性能,通过原位反应向复合材料的界面引入了低熔点金
属Bi.研究了涂层质量分数对涂覆后复合材料室温力学性能和阻尼性能的影响.结果表明,复合材料的力学
性能随着涂层质量分数的增加而降低;复合材料的阻尼性能则随涂覆量的增加而增加.涂覆复合材料的室温
阻尼值不仅强烈依赖于晶须表面涂覆物的质量分数而且依赖于应变振幅.涂覆复合材料在较低应变条件
(4×10-4)下出现一个由位错机制产生的阻尼峰.当应变振幅超过6x10-4,界面滑移成为主要的阻尼机制 相似文献
11.
In order to in situ measure chemical parameters of deep-sea water and hydrothermal fluids at midocean ridge(MOR), it is necessary to use high temperature and high pressure chemical sensors.Developing new sensors is essential to measure in-situ pH and other chemical parameters(dissolved H2, dissolved H2S) of deep-sea water and hydrothermal fluids in a wide temperature range(2℃―400℃) at MOR vents.The YSZ(Yttria Stabilized Zirconia, 9%Y2O3) ceramic-based(HgO/Hg) chemical sensors possess excellent electrochemic... 相似文献
12.
For developing TiO based imitated gold materials, the wettabilities of Fe and Fe-Cr-Ni-Ti on TiO were studied. The results
indicated that the wettabilities of Fe and Fe-Cr on TiO were poor, and their wetting angles were about 90° at melting point.
The wetting angles reduced with the increase of wetting temperature, but the influence of temperature was small. Fe and Fe-Cr
containing Cr 50% or less could react with TiO on the interface to form Fe2Ti and Ti2O3, but this did not improve the wettability effectively. When Ni-Ti was added into Fe-Cr alloy, Ni3Ti was formed on the interface, which can reduce the interface energy, improve the wettability, and prevent the formation
of Fe2Ti and Ti2O3. The wetting angles could go down to about 40° when 3% Ni-Ti was added to Fe-Cr alloy.
Biography of the first author: LI Qing-kui, Dr., senior engineer, born in August 1966, majoring in rare metal materials. 相似文献
13.
Three-dimensional hierarchical Co3O4 microstructures decorated with Ag and Cu oxides were prepared via displacement reaction and subsequent annealing treatment. Photocatalytic properties measurements revealed that the photocatalystic activities of CuO/Co3O4 composites (Co3O4 microstructures decorated with CuO) were enhanced while those of Ag2O/Co3O4 composites (Co3O4 microstructures decorated with Ag2O) were reduced, when compared with those of pure hierarchical Co3O4 microstructures toward the degradation of methyl orange. In addition, CuO/Co3O4 composites exhibited an excellent recyclability ability of photodegradation. The electrochemical properties test indicated that both of the composite oxide electrodes exhibited excellent pseudocapacitive performance with relatively high specific capacitance and good long-term cycling stability. With the increase of the loaded Ag2O and CuO dosages deposited on the Co3O4 microstructures surface, the specific capacitance values of the composites were increased. Ag2O/Co3O4 composite electrodes showed higher specific capacitance values and better cycling stability than CuO/Co3O4 composite ones. 相似文献
14.
Electric contact material of Ag/SnO2 was successfully synthesized by in situ process method. The interface structure was characterized by high-resolution transmission electron microscopy (HTEM) and
simulated at atomic scale on computer. The mean-square displacements of atoms near the interface were calculated, and the
results showed that near the interface both Ag side and SnO2 were mismatched and this effect decays rapidly far from the interface. By inspecting the calculated density of states (DOS),
we found that the electric-conductivity of this composite material was decreased because of the localized 4d and 2p electrons
of Ag and O near the Fermi surface, respectively. Electron density changed acutely across the interface, so that there was
no extra compound precipitated. A micro-electric field also formed in the whole material due to the interface structure, and
this may affect the electron conduction and the related electric-conductivity of the composite. It is found that the interface
cohesive energy of Ag (111)/SnO2 (200) was −3.50 J/m2, which is higher than the experimental results.
Supported by the National Natural Science Foundation of China (Grant No. 2008CB617609), the Natural Science Foundation of
Yunnan Province (Grant No. 2006E003Z) and Science Innovation Foundation of Kunming University of Science and Technology 相似文献
15.
xNi/10NiO-NiFe2O4 (x=5, 10, 17) cermets and those doped with 1% BaO (mass fraction) were prepared by cold isostatic pressing at 200 MPa and sintering
in nitrogen atmosphere at 1 473 K. The effects of BaO addition on relative density, microstructure and electric conductivity
of cermets were investigated. The results show that relative densities of xNi/10NiO-NiFe2O4 cermets (x=5, 10, 17) doped with 1% BaO at 1 473 K in nitrogen atmosphere are increased by 0.49%, 1.45% and 2.99% compared with those
of the undoped BaO cermets, respectively. Moreover, the electric conductivities (21.98, 28.37 and 50.10 S/cm) of xNi/10NiO-NiFe2O4 cermets (x=5, 10, 17) doped with 1% BaO at 1 233 K are improved compared with those (18.70, 22.79 and 39.58 S/cm) of xNi/10NiO-NiFe2O4 cermets (x=5, 10, 17), respectively. This indicates that perhaps the addition of BaO or formation of BaFe2O4 and Ba2Fe2O5 has an active effect on electric conductivities of xNi/10NiO-NiFe2O4 (x=5, 10, 17) cermets. 相似文献
16.
Cu、Ag、Au价电子结构参数统计值及熔点的理论研究 总被引:2,自引:1,他引:1
基于“固体与分子经验电子理论”(EET),分析了Cu、Ag、Au的价电子结构,计算了一组表征金属单质性质的价电子结构参数统计值E'A,T'm ,利用价电子结构参数统计值讨论了Cu、Ag、Au的熔点问题。计算结果表明,E'A 值越大,其对应金属的熔点越高,且E'A 的变化趋势与实验相吻合;Cu、Ag、Au熔点的统计值分别为T'Cum=1351.0K、T'Agm=1126.2K、T'Aum=1305.0K,相应的实验值偏差依次为0.41%、8.82%、2.33%。 相似文献
17.
张华煜 《武汉理工大学学报(材料科学英文版)》2014,29(5):1039-1043
Cf/Cu composite was prepared by vacuum melting infiltration. Ti and Cr were doped to the Cu alloy to improve the wettability between Cu and carbon. The microstrueture was investigated by XRD, SEM and EDS. The arc erosion rate of Cf/Cu composite was investigated in vacuum. The results showed that the Ti and Cr could improve the wettability between Cu and C/C preform and the infiltration ability of Cu into C/ C preform greatly. A TiC interface formed between the fibers and matrix. The good bonding between the fiber and matrix guaranteed that part of the Cu matrix can still be bonded on the fibers even when the material was exposed to the plasma. Consequently, the carbon fibers were protected from the erosion. In comparison, Cu was completely consumed by the arc erosion. Hence, the graphite was eroded and presented a cauliflower-like morphology. Therefore, the prepared C/Cu bad better ability to resist the arc erosion, compared with common Cu-C material. 相似文献
18.
19.
The isothermal section of Ag-Ti-Zr ternary system at 1023 K was determined by diffusion triple and electron probe microanalysis. The results indicate that four binary intermetallic phases of AgTi, AgTi2, AgZr and AgZr2 are found in Ag-Ti-Zr ternary system at 1 023 K. AgZr2 and AgTi2 form a continuous solid solution, namely Ag(Ti,Zr)2. Four three-phase regions: AgTi AgZr Ag, AgTi AgZr Ag (Ti, Zr)2, α-Zr β(Ti, Zr) Ag (Ti, Zr) 2 and α-Ti β(Ti, Zr) Ag (Ti, Zr)2 exist in the isothermal section. No ternary compound is observed. 相似文献
20.
An alloy steel/alumina composite was successfully fabricated by pressureless infiltration of X10CrNi18-8 steel melt on 30%(mass fraction) Ni-containing alumina based composite ceramic(Ni/Al2O3) at 1 600 ℃.The infiltration quality and interfacial bonding behavior were investigated by SEM,EDS,XRD and tensile tests.The results show that there is an obvious interfacial reaction layer between the alloying steel and the Ni/Al2O3 composite ceramic.The interfacial reactive products are(FexAly)3O4 intermetallic phas... 相似文献