Preparing Microcomposite Powders Doped with Antimony Dioxide and Properties of Thick Films Based on Those Powders

The goal of the work reported here was to develop a method of applying glass nanolayers of variable thickness to Sn_0.9Sb_0.1O₂ particles and to investigate how this affects the electrical properties of thick-film resistors. We prepared Sn_0.9Sb_0.1O₂ powders by calcinating coprecipitated tin and antimony hydroxides. Thin layers of aluminum, barium, and boron compounds were then precipitated from aqueous solutions onto powder particles. Nanolayers of glass in the BaO ― Al₂O₃ ― B₂O₃ system were obtained by dissolution followed by heat treatment. Resistive thick films made from such microcomposite powders have a higher resistivity than do those prepared by traditional methods and that resistivity changes little after repeated heat treatments. The thermal coefficient of electrical resistance decreases with increasing thickness of the glassy layer on the surface of the conducting particles.

     

Effect of Electrode Material on the Electrical Properties of Tin Dioxide Thick Films

Powder Metallurgy and Metal Ceramics - The influence of electrode materials made of Ag-containing paste and Ni3B-based paste on the properties of fine SnO2 thick films is studied. The...     

Features of Preparing Nano-Size Powders of Tetragonal Zirconium Dioxide Stabilized with Yttrium

The effect of wet chemical synthesis parameters on the properties of nano-powders of zirconium dioxide stabilized with yttrium is studied. Features of nano-powder synthesis by the oxalate, hydroxide and thermal hydrolysis of a sol methods are determined. Nano-size zirconium dioxide powder stabilized with 3 mole% yttrium is prepared by hydrothermal coprecipitation from a sol of metal chlorides and urea followed by dispersion and calcination. The possibility of controlling particle morphology by changing synthesis conditions, subsequent treatment and ultrasonic dispersion of the powder, and the calcination temperature-time schedule are studied by experiment. A method is developed for optimizing particle morphology (level of aggregation (agglomeration capacity)) and size. Non-agglomerated zirconium dioxide powder consisting of uniform nanosized (about 45 nm) aggregates of primary crystals is synthesized. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(443), pp. 28–42, May–June, 2005.     

掺杂镧的钡、锂铁氧体粉末的微波吸收特性

利用柠檬酸溶胶-凝胶自蔓延法合成掺杂镧的磁铅石型系列M型钡铁氧体 (La0.5Na0.5)xBa1-xFe12O19(x=0,0.1,0.3,0.5)和尖晶石型锂铁氧体Li0.5LaxFe2.5-xO4(x=0,0.005,0.015,0.025),并对镧的含量对铁氧体的吸波性能的影响进行了对比研究.实验结果表明,添加适量的镧能显著地改善铁氧体的吸波性能;掺杂量为x=0.3的钡铁氧体和x=0.015锂铁氧体对微波吸收最佳.     

Effect of Pulsed Laser Radiation on the Properties of Resistive Thick Films Based on Nickel and Barium Borides

We have used atomic force microscopy to study the surface morphology of resistive thick films based on powders of nickel and barium borides and a glass binder, treated with laser radiation. We used x-ray phase analysis to study the phase composition of these films. We have observed a change in the surface morphology, the phase composition, and the electrical resistance of the studied films as a function of the laser radiation energy.     

Effect of Residual Stresses on Electrophysical Properties of High-Ohmic Thick Films Based on SnO 2 ― Sb

We have studied the effect of a mismatch between the thermal coefficients of linear expansion for the current-conducting phase and the glass on the electrical properties of composite thick films based on Sn_0.93Sb_0.07O₂. The physical explanation of the results obtained is connected with the appearance of residual stresses in the film on cooling during heat treatment.     

Laser Treatment of Thick Films Based on Powder Composites of Nickel Boride

The thermophysical parameters (coefficients of thermal and temperature conductivity, coefficient of reflection of the laser beam) of resistive thick films (RTF) of powder composites based on Ni₃B and glass were determined. Coefficients of thermal conductivity were calculated using the theory of general conductivity for a multicomponent system. The coefficient of diffuse reflection was calculated from the indicatrix of dispersion of the laser radiation. The parameters obtained were used to calculate the dependence of surface temperature of a thick film under the action of pulsed laser radiation on the duration and energy of the impulse and the radius of the laser spot.     

超细25%NiCr-Cr_3C_2粉末制备及HVOF涂层性能研究

本文采用超细碳化铬粉末通过团聚烧结工艺制备球形25%NiCr-Cr3C2复合粉末,使用超音速火焰喷涂工艺制备耐高温磨损涂层,分析了超细25%NiCr-Cr3C2复合粉末的化学成分和表面形貌,通过涂层的结合强度和显微硬度与常规粉末的对比实验,研究超细Cr3C2颗粒对超音速火焰喷涂涂层的性能影响。     

纳米氧化锆喷涂材料的制备及表征

采用聚合物网络法制备了具有纳米结构的氧化锆粉体,将粉末进行了喷雾干燥球形化制粒及等离子致密化处理。结果表明采用该方法制备的纳米结构的氧化锆粉末松装密度高、流动性好,表面光亮,有利于提高涂层的综合性能。     

Thermal Stability and Tribological Properties of Fluorinated Amorphous Carbon Thin Films Doped With Nitrogen

Nitrogen doped fluorinated amorphous carbon thin films（a-C:N:F）were prepared by radio frequency plasma enhanced chemical vapor deposition（rf-PECVD）under different deposited condition using CH4,CF₄,and N₂ as source gases.The thin films were annealed at different temperature.The influence of doped nitrogen on the chemical structure,tribological and thermal properties of thin films were investigated by Atomic force microscopy（AFM）,Fourier transform infrared absorption spectrometry（FTIR）,X-ray photoelectron spectrum spectra（XPS）,and thermogravimetry（TG）.The results indicated that the thin films presence a compact and smooth morphology surface after the nitrogen doped.After incorporation of nitrogen,the H atoms are replaced partially by the N atoms in the thin films.The degree of cross-linking of the carbon network in the thin films is enhanced.The chemical bonds of C=N,C≡N,and C-Nx（x=1,2,3）have formed in the films.The relative content of sp² graphite phase increases.The thermal stability temperature of the films deposited atγ=0.5（γ=N₂/[CF₄+CH₄+N₂]）is 420℃.The tribological properties improve greatly,and the friction coefficient of the a-C:N:F thin films ranges approximately from 0.20 to 0.36.     

Molecular Dynamics Simulations of Dislocation Activity in Single-Crystal and Nanocrystalline Copper Doped with Antimony

Recent experimental and simulation results have indicated that high-temperature grain growth in nanocrystalline (NC) materials can be suppressed by introducing dopant atoms at the grain boundaries. However, the influence of grain boundary dopants on the mechanical behavior of stabilized NC materials is less clear. In this work, molecular dynamics (MD) simulations are used to study the impact of very low dopant concentrations (<1.0 at. pct Sb) on plastic deformation in single-crystal and NC Cu. A new interatomic potential for low Sb concentration Cu-Sb solid-solution alloys is used to model dopant/host and dopant/dopant interatomic interactions within the MD framework. In single-crystal models, the strained regions around the Sb atoms act as heterogeneous sources for partial dislocation nucleation; the stress associated with this process decreases with increasing Sb concentration. In NC models, MD simulations indicate that Sb dopants randomly dispersed at the grain boundaries cause an increase in the flow stress in NC Cu, implying that Sb atoms at the grain boundaries retard both grain boundary sliding and dislocation nucleation from grain boundary regions.     

不同生长温度对Ga掺杂ZnO透明导电薄膜性能的影响

采用磁控溅射方法在普通载玻片衬底上制备了Ga掺杂的ZnO(GZO)透明导电薄膜,并研究了不同生长温度对GZO透明导电薄膜的结构性能、电学性能及光学性能的影响.制备的GZO透明导电薄膜均沿(002)方向的择优取向生长,薄膜的表面形貌为蠕虫状,表明薄膜内存在较大的残余应力.随着生长温度的升高,GZO薄膜的电阻率先减小后增大,在生长温度为250℃时,薄膜的最低电阻率为1.91×10-3 Ωcm.不同生长温度下所制备的GZO薄膜在可见光波段的平均透过率均大于90％,薄膜具有优异的光学特性.     

掺Gd-CdTe薄膜的XPS研究

应用双源法真空蒸发制备掺Gd的CdTe薄膜,并借助XPS对其进行组份分析。实验表明,Gd掺杂的CdTe薄膜的组分为Cd、Te、O、C、Gd等元素,其中C、O主要以物理吸附方式存在于薄膜表面;Cd、Te元素的存在方式为CdTe化合物及其氧化物形式;而Gd元素由于碳污染的原因在其表面未曾出现,只在刻蚀过程中出现;深度剥蚀分析表明在样品内部Cd元素的含量大于Te元素的含量,且接近于1∶0.8,趋于稳定。     

Influence of Shock Wave Treatment of Boron Carbide Powders on the Structure and Properties of Hot-Pressed Polycrystals Based on Such Powders

The influence of deformation pre-treatment (milling in a planetary mill and shock-wave treatment) of B₄C powders of different size composition on their structure as well as the structure and mechanical properties of samples that have been hot-pressed from these powders is investigated. It is shown that treatment by shock waves produces a substantial change in the structure of the powders, and this tends to increase the mechanical properties of the polycrystalline cakes. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(444), pp. 118–127, July–August, 2005.     

Complexation-Coprecipitation Synthesis and Characterization of Erbium and Antimony Doped SnO2 Conductive Nanoparticles

Er was used as a dopant for the first time in preparing conductive powder to improve its performance. Er and Sb doped SnO₂ conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb₂O₃ and Er₂O₃ as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.29 Ω·cm; TG/DSC curves showed that the precursors lost weight completely before 750 °C; FTIR spectrum showed that the vibration peak were wide peak in 711 × 600 cm⁻¹; the Er and Sb doped SnO₂ conductive nanoparticles had intense absorption in 4000 × 1600 cm⁻¹; Er and Sb doped SnO₂ had a structure of tetragonal rutile; complex doping was achieved well by complexation-coprecipitation method and was recognized as replacement doping or caulking doping; TME showed that the particles were weakly agglomerated, the size of the particles calcined at 800 °C ranged approximately from 10 to 30 nm.     

Preparation and Luminescence Properties of LB Films Based on 4-Hexadecyloxybenzoic Terbium

LB films of 4-hexadecyloxybenzoic-terbium by using the subphase containing Tb^3 were prepared. The mono-layer behavior of 4-bexadecyloxybenzoic acid (HOBA) on the subphase containing rare earth ions was studied. IR and UV spectra show that the rare earth ions were bound to carboxylic acid head groups and the coordination took place between the polar head group and the rare earth ions. The luminescence spectra show that the LB films have the fine luminescence properties, and the LB films emit strong luminescence under UV light irradiation.     

Complexation-Coprecipitation Synthesis and Characterization of Neodymium and Antimony Doped SnO2 Conductive Nanoparticles

Nd and Sb doped SnO2 conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb2O3 and Nd2O3 as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC/DTG, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.12 Ω·cm. TG/DSC/DTG curves show that the precursors lose weight completely before 750 ℃. FTIR spectrum shows that the vibration peaks are wide peaks in 731～617 cm-1, and the Nd and Sb doped SnO2 conductive nanoparticles have intense absorption in 4000～2000 cm-1. Nd and Sb doped SnO2 have a structure of tetragonal rutile, and complex doping is achieved well by complexation-coprecipitation method and is recognized as replacement doping or caulking doping. TME shows that the particles are weakly agglomerated, and the size of the particles calcined at 1000 ℃ ranges about 10 nm to 30 nm.     

稀土掺杂钼制品的组织和性能研究

采用液-液掺杂工艺制得稀土掺杂钼粉及钼(合金)坯,通过调整掺杂稀土的种类及含量考察了其对钼粉及钼(合金)坯组织及性能的影响,结果表明,掺杂稀土的种类和掺杂含量的变化对Mo - La -Y复合粉体的形貌及尺寸的影响不明显;钼(合金)坯基体颗粒总体上随掺杂含量的增加而变细,而在相同掺杂含量下,双元掺杂比单元掺杂的细化作用更...