Fig. 1. Surface morphology of unpainted substrate

Fig. 2. Schematic of nanosecond laser cleaning optical path

Fig. 3. Cleaning effect of nanosecond pulse laser with different pulse frequencies and pulse widths

Fig. 4. Cleaning effect of nanosecond pulse laser with different average laser powers

Fig. 5. Surface morphologies of samples cleaned by nanosecond pulse laser. (a) Sample 5#; (b) sample 8#; (c) sample 9#

Fig. 6. Defect size on the surface of samples cleaned by nanosecond laser. (a) Sample 5#; (b) sample 8#; (c) sample 9#; (d)sample cleaned under the conditions of laser power of 600 W，pulse width of 60 ns，and pulse frequency of 20 kHz

Fig. 7. Surface roughness and crater depth of samples cleaned by laser at different laser powers and original substrate

Fig. 8. EDS analysis of the surface of original substrate and sample cleaned by nanosecond pulse laser. (a) Original substrate; (b) sample 8#

Fig. 9. Paint removal thickness and substrate damage thickness under different laser powers with pulse width of 60 ns and pulse frequency of 20 kHz

Fig. 10. Surface microhardness of original substrate and sample cleaned by nanosecond pulse laser