HIGH-RESOLUTION ELECTRON-MICROSCOPY OF THE SILICON-CARBIDE ALUMINUM CARBIDE INTERFACE

The interface of single-crystal SiC and Al brazed at 1273 K is investigated by high-resolution electron microscopy. The orientation relationship of SiC to the Al4C3 reaction layer that forms between the SiC and the Al can be expressed as (0001)SiC parallel-to (0001)Al4C3 and [1100BAR]SiC parallel-to [1100BAR]Al4C3. Furthermore, a very thin (two tetrahedral layers thick) transition phase and misfit dislocations are observed between the SiC and Al4C3 lattices. The structure of the transition phase is discussed based on the high-resolution electron microscopy, the stacking of the (Al,Si)C4 tetrahedral layers, and the charge balance. The same reaction product, with the same orientation relationships, is observed at the interface of a polycrystalline SiC and Al brazed joint.