Fig. 1. Alloy surface after laser alloying treatment

Fig. 2. SEM morphologies of alloys with three ratios. (a1) Morphology of sample 1 at low magnification; (a2) morphology of sample 1 at high magnification; (b1) morphology of sample 2 at low magnification; (b2) morphology of sample 2 at high magnification; (c1) morphology of sample 3 at low magnification; (c2) morphology of sample 3 at high magnification

Fig. 3. SEM scan patterns of alloys with three ratios

Fig. 4. XRD patterns of three kinds of metals and metal composition corresponding to each peak

Fig. 5. Hardness distribution curves in alloyed layers of three samples

Fig. 6. (a) Metal surface area without large bacterial community; (b) molten pool with much dead E. coli community

Fig. 7. Surface morphologies of alloy samples observed by SEM before and after corrosion with saline water for three months. (a1) Surface morphology of sample 1 before corrosion; (a2) surface morphology of sample 1 after corrosion; (b1) surface morphology of sample 2 before corrosion; (b2) surface morphology of sample 2 after corrosion; (c1) surface morphology of sample 3 before corrosion; (c2) surface morphology of sample 3 after corrosion