Coating of Y_2O_3 additive on Al_2O_3 powder and its effect on the wetting behaviour in the system Al-2O_(3p)/Al

摘要

A1_2O_3 powder was coated with Y_2O_3 percursor generated by in situ precipitation of Y(NO_3)_3·6H_2O in aqueous solution. After calcining at high temperature, the precursor was completely transformed into a crystalline Y_2O_3, and Y_2O_3-coated A1_2O_3 powder was obtained. Transmission electron microscope (TEM), high resolution electron microscope (HREM) observation and elemental analysis clearly showed that the Y_2O_3 was successfully coated on the surface of the A1_2O_3 particles. The coated powders were also characterized by energy dispersive spectrum (EDAX) and X-ray diffractometry (XRD). The wetting behaviour of molten aluminum on the coated A12O3 powders was investigated by the sessile drop method. Due to the introduction of Y_2O_3, the wettability of the coated-Al_2O_3 powders by liquid aluminum was dramatically improved in comparison with that of the as-received powders.