Fig. 1. Schematic diagram of the LIBS experimental setup

Fig. 2. Schematic diagram of sample ablation area

Fig. 3. LIBS spectrum of aluminum metal substrate

Fig. 4. Optical microscopic three-dimensional images of aluminum surface

Fig. 5. Variation pattern of Cr element LIBS spectral intensity on the metal (aluminum) surface with different microstructure shapes and cycles

Fig. 6. Variation trend of RSD of LIBS spectra under the surface of aluminum with four different microstructures as a function of microstructure cycle (Al)

Fig. 7. LIBS spectral intensity of Cr elements on the surface of aluminum with different microstructural shapes but the same cycle under dry conditions

Fig. 8. Variation trend of RSD of LIBS spectral intensity with changes in aluminum surface microstructure shapes under different microstructural cycles (aluminum)