Scanning electron microscope–cathodoluminescence (SEM-CL) analysis was carried out for the rapid phase identification of a single particle with the size of approximately 100 µm consisting of alumina (Al2O3) and spinel (MgAl2O4) phases. We selected this particle as the analyte because Al2O3 and MgAl2O4 are typical inclusions in steel, and their identification is important for steel production. Samples were prepared by pressing a mixture of Al2O3 and magnesia (MgO) powders heated at 1300 °C and copper powder into a pellet. The formation of a MgAl2O4 phase in the powder mixture of Al2O3 and MgO heated at 1300 °C was confirmed by X-ray diffraction analysis. CL images of samples were obtained using a camera attached to a SEM. We confirmed that Al2O3 and MgAl2O4 phases in a CL image produced blue and green luminescence, respectively, by comparing the CL image with elemental mappings of aluminum and magnesium in the sample obtained using an energy-dispersive X-ray detector attached to a SEM. We also observed the shift of a phase boundary between Al2O3 and MgAl2O4 with dozen micrometers scale by obtaining CL images of samples containing a mixture of Al2O3 and MgO powders heated at 1300 °C with different heat-treatment durations. The time required to obtain a CL image was 1 s. Thus, SEM-CL analysis will contribute to the rapid phase identification of Al2O3 and MgAl2O4 in a single particle.
- phase identification
- scanning electron microscope-cathodoluminescence