Preparation of CuO/Al_2O_3 Powders by Ultrasonic Spray Pyrolysis Method in High-Frequency Plasma

CuO/Al2O3 powders were prepared from aqueous solution by ultrasonic spray pyrolysis in the toil plume region of high-frequency inductively coupled plasma. The morphology of the initial powders varied with the atomic ratio of Cu/Al and the concentration in Cu(NO3)2-Al(NO3)3 solution. Al2O3 powders had spherical internal void structure and some shell fragments. CuO powders composed of a mixture of amorphous and ultrafine crystallite, some tens of nanometres in size. The compound powders of CuO/Al2O3, with Cu/Al atomic ratio 1:1, had a similar morphology to pure CuO powders. The diversity of fusing point between CuO and Al2O3 was the main factor to cause the different micro-processes of powder formation in h.f thermal plasma with a plate power about 1kW.