Applied Mechanics and Materials Vols. 217-219

Abstract: The porous Fe-Ni powders were successfully prepared by the gas nitriding, electroless plating and then removal of denitrogen & phosphorus under high temperature. The phases of the powders were determined by X-ray diffraction (XRD) utilizing Cu Ka radiation. Scanning electron microscope (SEM) was used to characterize the morphology of the porous powders. The magnetic properties of the powders were measured by a vibration sample magnetometer (VSM). The result shows that the porous Fe-Ni-N powder was mainly composed of γ’-Fe4 N and FeNi3 while the porous Fe-Ni powders were comprised by Fe0.64Ni0.36 and Ni. The porous Fe-Ni powder has a good soft magnetic property with Saturation Magnetization of 113.5emu/g and coercivity of 162.9Oe.

Abstract: In order to protect carboniferous system layer in east Sichuan, it added microparticle filling agent in drilling fluid. It depended on the physical truth and principle of protecting hydrocarbon reservoir technology which used in drilling fluid. According to the property of filling agent, it studied fluid loss control agent CKH-1, calcium carbonate superfine powder, non-permeate pressure-bearing agent CY-1 and nanometer material. Dosage of CKH-1 was 1%, calcium carbonate superfine powder was 2%, CY-1 was 4% and nanometer material was 1% ,which were firmed via experiment of viscosity and fluid loss control. Microparticle filling agent was sequentially formed.

Abstract: Silicon carbide with diffierent granularity and three grain composition was used as raw material. Silicon carbide refractory material was prepared in oxidizing atmosphere at 1400 °C, 1450 °C and 1500 °C for 3 h. Performence of samples were researched by measurements of apparent porosity, bulk density, bending strength at room temperature, thermal shock resistance and thermal expansion rate, and analyzed by SEM. The results showed that samples sintered at 1400 °C have low thermal expansion rate and apparent porosity, high bending strength and bulk density, good thermal shock resistance, compact texture as well. It can be deduced that (1.0-0.5mm) / (0.5-0.1mm) / (45μm) / (5μm) = 50 / 17/ 20/ 13 is the best grain composition to improve integrated performance of silicon carbide refractory material.

Abstract: 0~1.5mol% MnCO₃ doped ZnO-Pr₆O₁₁-Co₂O₃-Cr₂O₃ varistor ceramics were synthesized by conventional oxides mixing procedure. The effect of MnCO₃ variations on the microstructure, phase constituents and electric field–current density (E-J) characteristics of the ceramics were studied by SEM, XRD examinations and standard E-J test. The result showed the electrical nonlinearity exponents and breakdown voltage of the ceramics increased from 38 and 1296V/mm of the un-doped one to 52 and 1420V/mm respectively with the addition of 0.5mol% MnCO₃; meanwhile, the leak current density was reduced from 4.35μA/cm2 to 2.05 μA/cm². Further doping MnCO₃ deteriorated the overall varistor properties of the ceramics by remarkably decreasing the density of the ceramic, and the main reason causing the density drop was ascribed to the hindering effect of the well dispersed perovskite-like Pr_0.95Mn_0.9393O₃ particles formed mainly within the ZnO grain boundary areas.

Abstract: Assisted by Ag nanoparticles, Si substrates were etched in aqueous solutions containing hydrofluoric acid (HF) and hydrogen peroxide (H₂O₂) with different volumes of etching solution. The etching morphology of Si wafers was found to be affected by the volumes. In etching solutions with smaller volume, the pores were created; in etching solutions with larger volume, the nanostructure composed of nanowires and nanopores (pores+wires nanostructure) were generated. In addition, the lengths of these Si nanostructures increased with the increase of the etching volume. Possible formation mechanism for this phenomenon was discussed.

Abstract: By four-point bending tests on the reinforced concrete beams with emulsified asphalt of different parameters, cracks, deformation and bearing capacity were observed and recorded during destructive process, and then a comparison were made between the experiment results and those of ordinary reinforced concrete beams. The results prove that lower emulsified asphalt dosage (1% to 3%) can significantly improve the overall deformation of reinforced concrete beams; while higher asphalt emulsion parameters (5% to 7%) reduce the beam intensity and do not improve the toughness and overall deformation capacity.

Abstract: Fire retardant performance is an important indicator of fire-resistant fabric, and a major part of fabric protective properties, which has a great relationship with raw materials and weaving processing parameters of weaving. In this paper, basalt fiber were used to make fire-resistant fabric due to the superior properties of heat resistance, anti-oxidation, radiation, insulation of noisy and heat, filtration and high compression strength and shear strength. The fabrics of different weaves were produced on a sample loom. Then the properties, such as abrasion durability, fire resistance, reaction to acid and alkali were measured for evaluation. The results revealed that basalt fiber has great advantages for producing fire-resistant fabric.

Abstract: Nanometer europium oxide-doped titania particles were synthesized and electro-rheological fluids (ERFs) were prepared by reactions of those particles and hydroxyl silicone oil. The characteristics of particles were studied by transmission electron microscope, energy spectrum analysis and X-ray diffraction. The results show that europium oxide solid dissolve in titania and deposit on surface of titania , titania crystal become irregular and even particle size increase. Dielectric constant of titania is 3.25 and doped titania is 5.5. Viscosities and shear stresses of ERFs increase with electrical field increasing and all have critical field (2KV/mm),their viscosities are 4500 pa.s and 6340 pa.s, respectively(E= 3.5kv/mm). Shear stress of titania ERF change into 200 Pa from 50 Pa and that of doped titania ERF change into 800 Pa from 100 Pa when electrical field increased into 3 kv/mm from 0v/mm. Grafting reaction between particle and hydroxyl silicone oil improve stability ratio from 44% to 80 after 144 h.

Abstract: Ethylene tar (ET) was utilized as raw material, 1,4-benzenedimethanol and trioxane as crosslinking agent to prepare condensed poly-nuclear aromatic resin (COPNAR). FT-IR, 1H-NMR, TGA, elemental analysis, and improved Brown-Ladner calculation were systematically conducted for ET, COPNAR, and COPNAR/graphite composites prepared via graphite molding. The ET average molecular structure parameters were calculated using improved Brown-Ladner method, the crosslinking agent was found an important factor for the COPNAR synthesis, and the obtained COPNAR and CONPAR/graphite composites exhibited highly beneficial heat resistance.

Abstract: Conductive polyaniline(PANI) was synthesized by chemical oxidative copolymerization , using dodecylbenzene sulfonic acid (DBSA)as doping agent. PANI-DBSA/ABS conductive films were obtained by solution blending method, using chloroform as organic solvents. The products were characterized by means of digital four-point probe meter, FT-IR spectroscopy, thermal gravimetric analysis (TGA) and inverted metallurgical microscope. The results indicate that PANI-DBSA has good solubility because dodecylbenzene sulfonic acid (DBSA) plays a good doping role in polyaniline. Composite films’ electric conductivity improves with the increasing content of PANI and the percolation threshold is about 10wt% when conducting network formed. TGA curves demonstrate that product’s glass transition temperature is much higher than acrylonitrile-butadiene-styrene resin, furthermore, the thermal stability of composite films also improves compared with polyaniline or resin.