Papers by Author: Ming Hao Fang

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: Anorthite good sintering properties and strength, there promotion prospects in oil and gas fields in the ceramic proppant fracturing. In this experiment, fly ash, coal and limestone as raw materials by high-temperature reaction sintering ceramics, Explore mineral composition, the sintering temperature of the final preparation phase of the resulting composition and physical properties of the impact, better product performance obtained at 1250 °C.

Abstract: Si₃N₄-SiC-C refractory composites were prepared under the condition of 1100 °C × 1 h with Si₃N₄ and SiC as the raw material and the sucrose and phenolic resin as the binder. The effects of the amount of the sucrose in the binder on the properties of Si₃N₄-SiC-C refractory composites were studied. The results indicated that increasing the ratio of sucrose in the binder can improve the properties of the materials.

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: Mullite material was prepared from quartz (SiO₂) and industrial alumina (γ-Al₂O₃). The effects of mineral composition and sintering temperature on the final phase composition and physical properties of mullite were investigated. The results shown that a large number of mullite phase was emerged in samples when the ratio of alumina to silica (A/S) was 2.55. At 1500 ^oC and 1600 ^oC, the flexural strength of the samples reached to 87.13 MPa and 89.50 MPa, respectively. Consider the environmental protection and energy saving, the optimal sintering temperature was 1500 °C.

Abstract: Super-grade bauxite, pure silicon carbide, andalusite and metal silicon were used as the raw materials to produce plastic phase mullite-SiC bricks. By analysis of the microstructure, physical and chemical properties, it proves that the introduction of metal plastic phase can improve the properties of bricks, such as lower porosity, higher cold crush strength, and wearing resistance. It also can improve the toughness, and effectively relieve the thermal and mechanical stress when using in cement kilns. By analysis of the comparison with MA spinel bricks and ordinary mullite-SiC bricks, the plastic phase mullite-SiC bricks have good thermal shock resistance and lower thermal conductivity. The result shows that the bricks can replace MA spinel bricks using in the transition zone of cement kilns and realizes the aim of saving energy and a long service life.

Abstract: TiN-Sialon-Corundum composites were synthesized from rutile and quartz by aluminothermic reduction nitridation (ARN) method. The effects of aluminum contents on the phase behavior and properties of products were investigated. At 1500 oC, the main phases of products ARNed for 4 h were large granular corundum, TiN and hexagonal columnar Si₃Al₃O₃N₅. In addition, small TiN crystal particles distributed around the Si₃Al₃O₃N₅. It suggested that TiN-Sialon-Corundum composites were successfully fabricated by ANR method at 1500 °C for 4h. With increases in the amount of aluminum contents, the compressive strength ,the flexural strength and the bulk density of the composite refractory increased while the apparent porosity decreased. When the the aluminum contents increased to 48.90%, the composites had the highest compressive strength (47.34MPa) ,flexural strength (27.70MPa), bulk density (2.27 g/cm³) and had the lowest apparent porosity (27.57 %).

Abstract: In this study, Ca²⁺ stabilized ZrO₂-SiC composite materials were prepared via carbothermal reduction, using natural zircon ore as raw material, CaO as additive, and black carbon as the reducing agent. The effects of synthesis temperature and CaO content on the phase composition of the products were investigated by XRD. The microstructure and micro-area chemical analysis of the products were characterized by SEM and EDS. The results indicate that: (1) Ca²⁺ stabilized ZrO₂-SiC composite materials could be prepared from natural zircon ore with CaO addition between 1500°C and 1600°C for 4 hours by carbothermal reduction process. (2) The synthetic temperature has an important influence on the phase composition of the carbothermal reduction products of zircon. The production of m-ZrO₂ and t-ZrO₂ got obviously enhanced with increasing temperature from 1500°C to 1600°C. (3) At the same synthetic temperature, Ca²⁺ stabilized ZrO₂ got enhanced with increasing adding amount of CaO. The optimized synthesis condition of Ca²⁺ stabilized cubic-ZrO₂/SiC composite materials is sintering at 1600°C for 4 hours with adding 40 mol% CaO as additive.