Fig. 1. Pore penetration detection based on laser-induced breakdown spectroscopy

Fig. 2. LIBS spectrum of the sample

Fig. 3. Relationship between parameter change and spectral intensity

Fig. 4. Spectral distribution at 100 ms

Fig. 5. Spectral distribution at 1.7 s

Fig. 6. Variation of emission line intensity with time

Fig. 7. Variation of spectral intensity of characteristic spectral lines with time

Fig. 8. Spectral intensity map of each stage in the process of hole making

Fig. 9. Morphology of hole and protective material in case of incomplete hole penetration

Fig. 10. Morphology of the hole and protective material in the case of full hole penetration

Fig. 11. Morphology of protective material under excessive penetration