Papers by Author: Zhao Hui Huang

Abstract: Al₂O₃-SiC composite powders are prepared by carbothermal reduction method using coal gangue as raw material and carbonaceous materials (such as coke, anthracite, and carbon black) as reducing agents. The optimum conditions are as follows: when the addition of coke or anthracite is 50%, the temperature is at 1600 °C for 5 h, and adding 50% carbon black’s best temperature is at 1600 °C for 4 h. Based on the formula of stemming used in an iron and steel factory, Al₂O₃-SiC-C series blast furnace stemming refractory was prepared by adding Al₂O₃-SiC composite powder. The results show that the addition of Al₂O₃-SiC composite powders has a positive influence on the apparent porosity, volume density, and bending strength of the refractory. The effect of the amount of Al₂O₃-SiC composite powder on the slag corrosion resistance of the blast furnace stemming refractory was also studied by the static crucible method.

Abstract: Sialon-SiC composite powders were synthesized from kyanite tailings through the carbothermal reduction nitridation (CRN) technique. Using Sialon-SiC composites to substitute Si₃N₄ composites via the CRN technique synthesize Sialon/Si₃N₄-SiC composite refractories. The phase composition, cross section morphology, and the substituent amount of Sialon-SiC composites impact on refractories mechanical properties were investigated, respectively. The optimized synthesis temperature for the CRN reaction was found to be 1550 °C for 4 h with the excess carbon 20%. The substituent amount of Sialon-SiC was 25%, the mechanical properties of Sialon/Si₃N₄-SiC composite refractories reached optimal performance, which bending strength value was 41.8 MPa and compression strength value was 61.6 MPa.

Abstract: ZrO₂ fibers and belts have been fabricated by heat-treating the hybrid fibers and belts which were prepared by electrospinning method. Fiber and belt properties, for instance, surface morphology, diameter of fibers, crystallization formation, etc. were investigated by various techniques, scanning electron microscopy (SEM), X-ray diffractometer (XRD), transmission electron microscopy (TEM), energy dispersive spectrum (EDS) included. It was found that more belts and thicker fibers appeared with increasing PVP content. Using N,N,N-trimethyl-1-dodecanaminium bromide (DTAB) can avoid formation of belts and reduce the diameter of fibers from a range of 270 to 750 nm to a range of 90 to 150 nm. It all obtained monoclinic ZrO₂ fibers and belts after heat-treating (respectively at 700, 800, 900 °C) hybrid fibers and belts. The higher temperature heat-treatment leads rougher fibers and belts.

Abstract: Cordierite samples were prepared using quartz sand tailings, industrial alumina and magnesite tailings as raw materials by high-temperature reaction. The influence of mineral composition and sintering temperature on the final phase composition and physical properties of cordierite were studied. The results shown that a large number of cordierite generated at 1300 °C. When the ratio of Al₂O₃/SiO₂ equals to 1.08, the flexural strength of samples increased to 27.66 MPa.

Abstract: The performance and phase behavior of Quartz - Aluminum Matrix Composites at different temperatures were studied. Quartz aluminum matrix composites were prepared by powder metallurgy method. At the temperature that was less than 660.4°C(the melting point of aluminum), a portion of quartz was happened decomposition and revivification to silicon, most aluminum still existed in the form of metal aluminum. All quartz were happened at the temperature that was higher than 660.4°C. When the temperature is 700°C, the compressive strength of S5(added 40% quartz) is up to 46.02MP. The higher the value of compressive strength was, the less the amount of quartz were happened decomposition. At the temperature more than the melting point of aluminum, Quartz was revivification to silicon, aluminum is oxidized to Al₂O₃. When the amount of silica exceeded 10%, the mechanical properties of composites declined consequently.

Abstract: Alumina from sericite phyllite was extracted by the way of limestone self-pulverization sintering technique. The key technical processes, including self-pulverization sintering, clinker leaching reaction and the carbonation decomposition, were investigated systematically. The results showed that the main phases of pulverized clinker consisted of γ-C₂S and C₁₂A₇, and the self-pulverization rate was 95% . The dissolution rate of Al₂O₃ clinker could reach 86.7% when the concentration of Na₂CO₃ solution was 7% and the solid-liquid ratio was 1:3. The Al(OH)₃ prepared at 80°C carbonation temperature and pH=10.5 was relatively pure, with hexagonal plate-like crystals. The α-alumina could be acquired by calcination at 1200°C with the content of 99.71% Al₂O₃ and 0.02% Na₂O. This work provided optimal technological parameters for effectively extracting alumina from the sericite and other inexpensive non-bauxite mineral resources with A/S ratio lower than 1.

Abstract: Tourmaline has characteristics of repeatedly producing electric dipole polarity transformation. Using FTO glass substrate coated with conductive films as raw materials, the research aims to prepare functional glass materials, which have spontaneous polarization effect, absorption of wideband electromagnetic radiation and high visible light transmittance. This paper applied Magnetron Sputtering deposition technique, studying on tourmaline as target, sputtering on conductive FTO glass, using multiple means to measure and analyze the surface morphology, component, structure, electrical and magnetic properties. And the functions of tourmaline as composite electromagnetic shielding films are also discussed in the paper.

Abstract: Doping perovskite structure ceramics constitute an important type of solid oxides fuel cell (SOFC) cathode materials. In this study, BaCe1-xTaxO3+δ powders were prepared by solid state reaction at 1500oC for 4h. BaCe1-xTaxO3+δ ceramics were pressureless sintered at 1600oC for 5h. The results indicated that the relative density of BaCe1-xTaxO3+δ ceramics reached the range of 84.15 - 90.88%. At the frequency of 1Hz, the conductivity of BaCe0.65Ta0.35O3+δ ceramic samples varied greatly, when the testing temperature rose from room temperature to 900oC in increments of 100oC. The highest conductivity was obtained at 600oC with the value of 6.74×10-5 S/cm.

Abstract: β-Sialon/Ti(C,N) composites were prepared using low and middle grade bauxite and ilmenite as raw material,while coke as reducing agent in high purity nitrogen atmosphere through carbothermal reducrion-nitridation(CRN).The main phases of low and middle grade bauxite are kaolinire(Al2O3•2SiO2•2H2O) and (Al2O3•H2O)2 and ilmenite mainly contain ilmenite(FeTiO3) and rutile(TiO2).The reaction products of bauxite are the β-Sialon(Z=3,Si3Al3O3N5) while those of ilmenite are TiC and Fe.The results showed that the main phases are β-Sialon,Ti(C,N),Al2O3 and Fe when the reaction temperature is at 1400°C holding for 4 hours(10wt% ilmenite and 90wt% bauxite as raw material).However,β-Sialon decomposes into 21R at 1450°C and into 15R and AlN at 1500°C.So 1400°C is selected as the proper temperature to synthesize β-Sialon/Ti(C,N) composites.At 1400°C,the β-Sialon crystals with the largest quantity grow well and show long column in shape.With the increase of the reacrion temperature β-Sialon begin to decompose,the β-Sialon crystals change to short columnar,with the number decreasing quickly.

Abstract: Mg²⁺2+,Al₃₊ Co-doped Li₃V₂(PO₄)₃/C powder was synthesized by sol-gel method under nitrogen. The crystal structure and micrograph ofLi₃V₂(PO₄)₃/C powder before and after doping was investigated by XRD, SEM and FT-IR. The effect of Mg2+/Al3+ Co-doping onLi₃V₂(PO₄)₃/C powder was discussed. The results indicated that Mg²⁺2+,Al₃₊ Co-doping did not change the crystal structure of Li₃V₂(PO₄)₃, but decreased the grain size of the as-synthesized powder. The FT-IR analysis indicated that weak Al-O bond was generated after doping.