ABSTRACT
The use of ‘non-chemical’ methods for modification of the properties of dispersed systems is of growing interest. Among other methods, irradiation with radiofrequency (RF) electric field may affect their properties. An example of a practical application would be to prevent hard scale formation in industrial pipes working at elevated temperatures. In the current study, a 44 MHz (60 V peak-to- peak, no-load amplitude) radiofrequency field was applied to aluminum oxide dispersion in water or NaCl solutions and then the zeta potential and the effective diameter were determined using a ZetaPlus instrument (Brookhaven Co.). Also, the oxide thin layer deposited on a glass plate was subjected to the field and then the free energy components were determined by the thin-layer wicking method. Moreover, the effect of RF field was also studied for the Al2O3 plates with preadsorbed Mg2+, Al3+, and OH− ions. It was found that the RF field affected all studied parameters; especially large changes in the acid–base free energy components were observed for the oxide surface possessing the preadsorbed ions.
