SLEEM study of MgAl₂O₄ at interface between Al ₂O₃ and matrix in Al₂O₃ /Al alloy composite materials

In the present talk, MgAl₂O₄ in the Al ₂O₃/Al-1.0mass%Mg₂Si alloy composite was also observed by a scanning electron microscope equipped with the low energy electron (SLEEM) adaptation aiming at examination of its morphology and orientation relationships to the AbO3 particles. Owing to its much smaller interaction volume of signal exciting electrons in the target and hence more localized information, together with a favorable combination of secondary (SE) and backscattered (BSE) electron signals, the SLEEM method provided much better readable and detailed images of all particles, their shapes and mutual orientations, in comparison with conventional SE and BSE images at the electron energies usually used in the SEM. MgAl₂O₄ (spinels) were formed on facets of Al₂O₃ as small particles, and their shape well corresponded to an octahedron consisting of 8 equiaxial triangles.