Abstract
The Wetting of fusion cast $Al_2O_3$ brick and $Al_2O_3 -ZrO_2$ brick by liquid Ag was studied by the sessile drop technique in Ar atmosphere. In this experiment the specimens were photographed per 2$0^{\circ}C$with increasing temperature from 96$0^{\circ}C$ melting point of Ag. And the method of photographing was carried out by shadow technique. The cosine of the contact angle increased linearly with increasing temperature in both systems. And the relation between the cosine of the contact angle and the temperature was Cos$\theta$=1.132+$0.75{\times}10^{-3}T$ for $Al_2O_3$ brick and Cos$\theta$=-1.706+$1.125{\times}10^{-3}T$ for $Al_2O_3 -ZrO_2$ brick In both systems the contact angle decreased as the surface of substrate became smoother. The work of adhesion which was 503.5ergs/$cm^2$ for $Al_2O_3$brick and 393.6 ergs/cm2 for $Al_2O_3 -ZrO_2$ brick at 96$0^{\circ}C$ increased parabolically with increasing temperature in both system.