Capacitor discharge joining of ceramics offer bonding without the damaging effects of extended heating times. Microstructures formed in alumina-AlxNiyYz -alumina joints were investigated using a combination of EDX and PEELS in a dedicated STEM. A distinct reaction layer is formed between alumina grains and the amorphous AlxNiyYz foil. This layer contains several interesting microstructural features. It has a yttrium oxide dominated matrix with spherical aluminum particles. An analytical microscopy characterisation of these features have been demonstrated.