Contact angle and surface tension measurements on a metal drop by image processing and numerical calculation

The purpose of this work is to establish solid/liquid contact parameters : contact angle, surface tension and work of adhesion, for drops of molten me tal on ceramic substrates. Referring to the literature, we can justify the use of the sessile drop method. After a judicious choice of the quantity of liquid for each drop, we have improved the performance of the measurement device. First, we have improved the definition of the drop picture. Then, w e have rationalised the programs of exploitation of drop profiles for the c alculation of the contact angle and the surface tension. Tests operated in various conditions such as high temperature show that the accuracy of the c ontact angle measurement is about one degree. This corresponds to a relativ e error of about 5 to 8% on the work of adhesion when contact angle is arou nd 150 degrees.