Contact angles and spreading kinetics of Al and Al–Cu alloys on sintered AlN

Wetting (both final contact angles and spreading kinetics) and bonding (Wa) of pure Al and Al–Cu alloys on sintered AlN are studied by sessile drop experiments under high vacuum at 1100°C. At this temperature, the process which controls the spreading rate is shown to be the deoxidation of AlN surface. The mechanical behaviour of solidified droplets on cooling can be explained satisfactorily taking into account two parameters: the work of adhesion of the alloys on AlN and the yield stress of the alloys.