Atomic observations at the reactive wetting front on SiC

Reactive wetting of a Ag-Cu-Ti molten alloy on a SIC substrate was observed in situ using a high-resolution transmission electron microscope. SIC diss olution and TIC nucleation and growth were repeated at the spreading front. The formation process of the interface between SIC and TIC was classified into two types depending on the nucleation site of the TiC. When the TIC nu cleated on SIG, the interface between SiC and TiC was coherent and two crys tallographic orientational relationships were observed. The stability of th ese relationships is discussed using a geometrical model. In contrast, when the TiC nucleated on preformed TiC, the TiC grew continuously with SiC dis solution.