Boron compounds are promising candidates for reinforcement of metals because of their high strength and stiffness at low specific weight. For composite fabrication the wetting behavior is important. Isothermal wetting of B 4 C, AlB 2 , CaB 6 , MgB 2 , and TiB 2 by liquid pure aluminum (99.5%) and the alloy AlSi10MgMn is studied at 700 C for 15 min in vacuum using the dispensed drop method. No wetting occurs during testing for all substrates. The contact angles remain constant for CaB 6 , MgB 2 , and TiB 2 , while for AlB 2 and B 4 C substrates a continuous decrease in contact angle value with time is observed. 1884 wileyonlinelibrary.com