Binghe Sun

Porous TiC Ceramics Derived from Wood Template

A porous TiC ceramic with a woodlike structure was prepared from wood template through tetrabutyl titanate vacuum-infiltration. The tetrabutyl titanate was first decomposed to TiO2, and then in-situ reaction between TiO2 and carbon template took place in the cellular wall at high sintering temperature. The original structure of wood was retained. In addition, the dimensional shrinkage of the pores after the removal of the residual carbon was different according to the difference of the wood density.

Performance improvement of industrial pure aluminum treated by stirring molten fluxes

Removal of inclusions from molten aluminum (A001) and aluminum grain refinement were studied by thermodynamic theory and a surface renewal kinetic model. After molten aluminum poured into the rotated molten flux in batches, the inclusions were transferred into the stirred molten flux, at the same time the trace impurities in molten flux diffused into the molten aluminum droplets. Thermodynamic theory shows that wettability of the inclusions in molten aluminum is worse than that in the molten active flux. Migration of the inclusions and diffusion of the trace impurities were described with the surface renewal kinetic model. Tensile tests show that the tensile strength of treated tensile sample (as-cast) was increased by 8.59%. The fracture cracks and the dimples were homogeneous and small as shown in SEM (scanning electron microscopy) photographs. Moreover, the quantities and sizes of the inclusions in the treated tensile samples were obviously fewer and smaller than that of in the untreated tensile samples as shown in metallographs and statistical results of an image analysis software. Meanwhile, the grain sizes of treated tensile samples were smaller than that of untreated tensile samples.

Corrosion resistance properties of enamels with high B2O3–P2O5 content to molten aluminum

Abstract Anticorrosive properties of borophosphate and boron-free enamels to molten aluminum were investigated using SEM and electron probe. Carbonates of alkali metal and alkaline earth metal were added in an appropriate weight ratio to achieve desired melting temperature of the enamels. SEM examination on the solidified interface between the enamels and aluminum alloy show that the enamels can spread slightly on aluminum alloy. For anticorrosive sample of borophosphate enamel, phosphorus was not detected by electron probe at the side of aluminum alloy near the interface, but silicon was detected in the silica-free enamels side. For the sample of boron-free enamels, however, phosphorus was found at the side of aluminum alloy near the interface. It was revealed that the enamels with high B 2 O 3 –P 2 O 5 content have high corrosion resistance to molten aluminum.

Effect of boron on removal of iron from aluminium melts

Abstract Effect of boron on iron removal and the feasibility of formation of iron borides in Al melt were studied. The iron composition was not reduced by the addition of boron. Analysis using SEM/EDX and XRD indicated the formation of titanium and vanadium borides in the melt and no iron borides were detected. Thermodynamic calculations proved that iron cannot react with the added boron in the melt to form iron borides under the experimental conditions, and the lowest Fe concentration that can be purified by boron addition is ∼11·7 wt-%.

THEORETICAL ANALYSIS FOR THE MOTION AND TEMPERATURE OF MELT DROPLETS IN SPRAY DEGASSING PROCESS

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.