Fig. 1. Schematic of nanosecond laser cladding

Fig. 2. Numerical simulation model

Fig. 3. Distribution map of three-dimensional temperature field when heat transfer time is 700 ns

Fig. 4. Sketch map of node position

Fig. 5. Variation of node temperature with time

Fig. 6. Temperature fields at different powers (t=700 ns). (a) P=10 W; (b) P=18 W; (c) P=26 W; (d) P=30 W

Fig. 7. Diagram of matrix remelting depth and molten pool depth

Fig. 8. Effect of laser power on size of cladding layer

Fig. 9. Ratio of matrix remelting depth to melting depth at different powers

Fig. 10. Temperature fields at different scanning speeds. (a) 4 m·s-1; (b) 10 m·s-1; (c) 12 m·s-1; (d) 16 m·s-1

Fig. 11. Size of cladding layer at different scanning speeds

Fig. 12. Ratio of matrixremelting depth to melting depth at different scanning speeds

Fig. 13. Temperature fields at different repetition rates. (a) 200 kHz; (b) 300 kHz; (c) 350 kHz;(d) 400 kHz

Fig. 14. Size of cladding layer at different repetition rates

Fig. 15. Ratio of matrix remelting depth to melting depth at different repetition rates

Fig. 16. Process programs of SY-PERC cell and BSL-PERC cell

Fig. 17. Silicon wafer after printing silicon paste and drying

Fig. 18. Surface topography of experimental wafer after laser cladding process

Fig. 19. Surface topography of silicon substrate after laser opening passivation layer