An IT800SHL JEOL scanning electron microscope (FEG SEM) equipped with an SSD Ultim Max 100mm2 detector (EDS Oxford system) was used for microstructural analysis. High precision elemental analysis was examined by using a Cameca SX Five electron microprobe (EMP) (40 points per sample). All samples for SEM imaging and microprobe testing were obtained from randomly selected crystallized beads embedded in epoxy resin, polished and carbon coated under vacuum.