Papers by Keyword: RuO₂

Abstract: In this paper, RuO₂-CB/MVQ composites were prepared through following steps. First, the nanoruthenium particles had been prepared by solvent thermo-deoxidization ways. Secondly, the nanoRuO₂ particles had been formed by oxidation reaction of nanoruthenium particles in air. Thirdly, the carbon black/silicone rubber mixed rubber was prepared by solvent mixing. Fourthly, the nanoruthenium particles were mixed into carbon black/silicone rubber mixed rubber by rubbing dispersion. Finally, vulcanization molding was carried out at certain preasure and temperature. The piezoresistive properties of CB/MWQ composite materials were tested with pressure-resistance testing systems designed ourselves. The test results showed that suitable amounts of RuO₂ could enhance the stability and creep of piezoresistive properties of CB/MWQ composite materials. The microstructure of CB/MWQ composite materials were analyzed with SEM and TEM. The characterization results showed that nanoRuO₂ particles dispersed in composite materials in nanolevel. These nanostructure could improve conductive net of carbon black, and reinforce crosslink net of silicone rubber. These factors had advantage to the stability of piezoresistive properties of CB/MWQ composite materials.

Abstract: P-type BiSbTe/RuO₂ composite was fabricated using a combined process of melting and spark plasma sintering. The XRD patterns showed that RuO₂ reacted with the matrix for the RuO₂ content of 1.0 wt% and 4.0 wt% samples. The measured thermoelectric properties showed that the highest electrical conductivity was obtained for the sample with 2.0 wt% RuO₂. The power factor (α²σ/κ) decreased with the increase of RuO₂ below 450 K. The lattice thermal conductivity was lower than that of BiSbTe over the whole temperature range for BiSbTe/2.0 wt% RuO₂.

Abstract: In this paper, synthesis of RuO₂ with uniform nanosized sphere-like morphologies by ultrasonic precipitation using ammonia is presented. The structures, properties and electrocatalytic performance of materials were characterized by XRD, FE-SEM, CV and polarization curve. FE-SEM photographs showed that the sample prepared by ultrasonic precipitation has a relatively narrow size distribution compared with the sample prepared by conventional precipitation with magnetic stirring. The CV and polarization curve for OER (oxygen evolution reaction) confirmed that electrochemical active surface area and OER activity of sample by ultrasonic precipitation are higher than that of sample by conventional precipitation under magnetic stirring.

Abstract: We report the growth of well-aligned RuO2/R-TiO2 heteronanostructures on sapphire (100) substrates by reactive magnetron sputtering using Ti and Ru metal targets under different conditions. The surface morphology and structural properties of the as-deposited heteronanostructures were characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and selected-area electron diffractometry (SAED). The FESEM micrographs and XRD patterns indicated the growth of vertically aligned RuO2(001) nanotubes and twinned V-shaped RuO2(101) nanowedges (NWs) on top of R-TiO2 nanorods under different sputtering pressures. TEM and SAED characterizations of the V-shaped RuO2 NWs showed that the NWs are crystalline RuO2 with twin planes of (101) and twin direction of [ 01] at the V-junction.

Abstract: The conductive composites in which nano RuO2 particles are dispersed throughout a glass matrix have been successfully fabricated by sintering at 850°C. The sensing properties of conductive composites were investigated in real time during tensile testing by measuring the electrical resistance. It is shown that the excellent sensing ability based on electrical resistance changes in the low strain range was due to deformation of conduction paths between nano RuO2 particles by brittle fracture of the glass matrix. The change of electrical resistance depends strongly on the volume percent of Al2O3 fiber reinforcement.

Abstract: The RuO2 thin films have been deposited onto glass substrates by rf reactive magnetron sputtering at different deposition conditions, such as different substrate temperatures, different sputtering pressures and different reactive gas pressures, using a metallic target. The deposited films have been characterized by the X-ray diffraction and Raman scattering. By analysis of data of the X-ray diffraction, it has been found that all the films are subject to a compressive stress. The residual stress in these films can be released by increasing the substrate temperature. In addition, the films, which have been prepared at the oxygen partial pressure higher than 1 x 10-3 mbar and at the total pressure lower than 6 x 10-3 mbar, show a quite high residual stress because the films peeled off automatically from the substrates when they were moved out from the vacuum chamber. Three Raman models (Eg, A1g and B2g) have been observed in all the Raman spectra. These Raman spectra have shown a strong relation with the residual stress in the films. As the residual stress increases, the Raman peaks move toward to the low wavenumber comparing to the standard value. In addition, the residual stress also results in the disappearance of the A1g Raman mode. In this work, these phenomena will be discussed.