Detection of calcium homogeneity distribution in magnesia-aluminum spinel using laser-induced breakdown spectroscopy

To further improve the yield of producing magnesium aluminum spinel and detect the distribution of sintering aid in raw materials, the Mg–Al spinel samples were prepared using MgO and Al₂O₃ as raw materials and CaO as sintering aids. Information on the distribution of the sintering aid Ca element in mixed samples was rapidly obtained by laser-induced breakdown spectroscopy (LIBS) mapping using a picosecond laser and a closed chamber filled with Ar gas. The optimal mixing time and environmental parameters of the raw materials were determined through optimization experiments, and the calibration models of Ca/Al and Ca/Mg were established with the intensities of Al and Mg characteristic lines as the internal standard. The correlation coefficient R², Root Mean Square Error of Calibration (RMSEC) and Mean Relative Error (MRE) of different calibration curves were evaluated. The feasibility of LIBS technique to detect the uniform distribution of sintering aids in Mg–Al spinel is verified by comparing with the images scanned by X-ray energy dispersive spectroscopy (EDS). Finally, we performed LIBS scans in the depth direction and obtained the spatial distribution of the Ca element. This work opens up a new research route for realizing the application of LIBS analysis in magnesia-aluminum spinel.