Fig. 1. Schematic of laser-induced maskless localized electrodeposition system

Fig. 2. Schematics of laser induced electrodeposition gold on stainless steel surface

Fig. 3. EDS analysis of 316L stainless steel substrate cross-section before and after laser scanning. (a) Before laser scanning；(b) after laser scanning

Fig. 4. CV curves of 316L stainless steel substrate before and after laser scanning. (a) Before laser scanning; (b) after laser scanning

Fig. 5. Current-time curve when energy of laser single pulse is 4 μJ

Fig. 6. Comparison of surface morphologies of gold coatings under different single pulse energy with 2D SEM images shown in insets. (a1)(a2) 1 μJ; (b1)(b2) 3 μJ; (c1)(c2) 5 μJ; (d1)(d2) 7 μJ; (e1)(e2) 9 μJ

Fig. 7. Comparison of roughness of gold coatings under different single pulse energy

Fig. 8. EDS diagrams and element contents of typical areas of gold coating under different single pulse energy. (a) 0 μJ (base plate); (b) 1 μJ; (c) 5 μJ; (d) 9 μJ; (e) element contents

Fig. 9. High-magnification morphologies of gold coatings under different laser scanning speeds. (a) 5 mm/s; (b) 10 mm/s；(c) 15 mm/s; (d) 20 mm/s

Fig. 10. Morphologies and profile curves of gold coatings under different laser scanning speeds. (a1)－(a3) 1 mm/s；(b1)－(b3) 5 mm/s; (c1)－(c3) 10 mm/s; (d1)－(d3) 15 mm/s; (e1)－(e3) 20 mm/s; (f1)－(f3) base plate

Fig. 11. SEM images of gold coatings under different laser pulse frequencies. (a) 500 kHz; (b) 1000 kHz; (c) 1500 kHz；(d) 2000 kHz; (e) 2500 kHz; (f) 3000 kHz; (g) 3500 kHz; (h) 4000 kHz

Fig. 12. SEM images of interval areas of square gold coatings under different laser powers. (a) 5 W; (b) 10 W; (c) 15 W；(d) 20 W; (e) 25 W; (f) 30 W; (g) 35 W; (h) 40 W

Fig. 13. EDS diagrams of square gold coating interval area when laser power is 5 W. (a) SEM; (b) O; (c) Fe; (d) element overlay; (e) Au; (f) Cr

Fig. 14. EDS diagrams of square gold coating interval area when laser power is 30 W. (a) SEM; (b) O; (c) Fe; (d) element overlay; (e) Au; (f) Cr

Fig. 15. Morphologies of coatings in bending test. (a)(b) Laser induced gold coating; (c)(d) direct electroplating gold coating

Fig. 16. Morphologies of laser induced gold coating before and after thermal shock test. (a) Before test; (b) after test

Fig. 17. Morphologies of coatings before and after corrosion test. (a)(c) Before corrosion test; (b)(d) after corrosion test

Fig. 18. Typical patterns prepared by laser induced electrodeposition. (a) Oval patterns with different sizes; (b)(c) Chinese characters