Fig. 4

SEM characterization of spark-generated Sn and Ti coatings deposited at a scanning velocity of 40 mm min-1 under non-magnetic and magnetic-field-assisted conditions. (a,b) Top-view images of Sn (1 pass) and Ti (3 passes) films deposited without magnetic field. (c,d) Corresponding cross-sectional SEM images showing film thickness and porous oxide-layer formation. (e,f) Top-view images of Sn and Ti films deposited under a 300 mT magnetic field (1 pass). (g,h) Corresponding cross-sectional SEM images of magnetically assisted coatings.