Wetting of AlN and TiC by Liquid Ag and Liquid Cu

The wetting of AlN and TiC by liquid Ag and liquid Cu was investigated by the sessile drop technique at 10 ⁻⁶ torr or less. An empirical relation was established between the cosine of the contact angle and the temperature or surface tension of the liquid drop. The critical surface tension for spreading and its physical significance are discussed. A method for estimating the surface energies of ceramics is proposed. The surface tension of TiC is estimated to be 1242±158 dynes/cm and that of AlN 990±110 dynes/cm. The surface tension of liquid Ag followed the equation γ _Lv (Ag) (dynes/cm) = 1092–0.14T (°C) and that of liquid Cu γ _LV (Cu) (dynes/cm) = 1462–0.27T (°C).