WETTABILITY STUDIES OF CUBIC BORON-NITRIDE BY SILVER-TITANIUM

In the present work the wettability of cubic boron nitride (BN) by titanium has been studied using BN-(Ag-Ti) as the model system. The method of sessile drop has been employed in the studies while heating the substrate and the metal to a temperature of 1000 degrees C under a vacuum of 3.10(-3) Pa. From the results of the studies it can be concluded that BN exhibits very good wettability by the Ag-Ti alloy. The contact angle, theta, is equal to 0 degrees after 15 min of keeping the system at 1000 degrees C. Calculated work of adhesion for the system studied is W-a = 3656 mJ/m(2). Such values of contact angle and work of adhesion must result from the chemical interactions that occur at the interface of the phases studied. Microscopic studies of the structure of the cross section of the interface layer, as well as the point and linear distributions of Ti, Ag, B and N, confirm that in this system a chemical reaction between boron nitride and titanium takes place. High chemical activity of titanium towards boron nitride makes it possible to use it as an additive for binding materials and solders.