Ge–Al and Sn–Al alloys capillary properties in contact with aluminum nitride

Experimental isotherms are presented for (1) wettability of AlN ceramics by Ge–Al and Sn–Al alloys, (2) surface tension and density of Ge–Al and Sn–Al alloys in the whole concentration range. Complex consideration of capillary characteristics of the melts under study is performed taking into account data available on thermodynamic activities of the melt components. The contact angle isotherms pass the minimum point for both systems. The contact angle value drops with Al addition more sharply for the Sn–Al system than for the Ge–Al alloys. This is in qualitative agreement with the higher thermodynamic activity of the components of the Sn–Al alloys. Sn decreases Al surface tension more than Ge. The reason for this is not only lower surface tension of Sn as compared to Ge, but also the higher thermodynamic activity of Sn in the Al melt.