Influence of ultrasonic waves on cobaltous hydroxide sol

Abstract

Ultrasonic agency (1 Mc/s 225 watts per sq. cm. output) can be successfully utilised for the preparation of rather a stable colloidal cobaltous hydroxide sol bearing a positive charge. On exposing this sol to ultrasonic waves, it becomes more stable. The specific conductivity and hydrogen ion concentration of the sol continuously increases with the time of exposure to ultrasonic waves. The viscosity of the sol decreases with the time of exposure to ultrasonic waves. The optical density and coagulation values with electrolytes also increase on exposing the sol to ultrasonic waves. The stability of the sol is probably due to the increase in positive charge on the colloidal particles as the hydrogen ion concentration of the sol has increased on exposure. The change in colour is due to transformation of cobaltous to cobaltic hydroxide by ultrasonic waves.