Influence of ultrasonic vibration on the wettability

In order to achieve low pressure or pressure-less infiltration of metal matrix composites with a non-wetting reinforcement/molten metal system, lowering a contact angle was investigated by applying ultrasonic vibration. The water droplet/paraffin coated substrate and molten aluminum/alumina pipe system, of which contact angles are more than π/2rad, were selected as a model system. The stepwise increment of ultrasonic power up to 11.6kW/m2 decreased the contact angle from 1.82 to 1.01rad. With a short period, the water droplet did not change its volume under ultrasonic vibration spread over on the substrate. Alternatively, when the alumina pipe with an inside diameter of 2.0mm was immersed in molten aluminum below 30mm from the surface at 1023K, the molten aluminum did not enter into the pipe. However, the infiltration of molten aluminum into the pipe was observed approximately 23mm from the pipe end by applying ultrasonic vibration. The improvement of apparent wettability by ultrasonic vibration is possible to apply to liquid infiltration process of metal matrix composites.