Figure 5 OM images of the microstructure at the bonding interface “A4”of bimetallic castings with different surface treatment methods of the gray iron inserts: (a) no treatment except for being cleaned; (b) salt membrane plating; (c) zinc barrel plating for 1 hour; (d) zinc barrel plating for 2 hours; (e) zinc barrel plating for 3 hours; (f) zinc rack plating for 1 hour

Figure 5
OM images of the microstructure at the bonding interface “A4”of bimetallic castings with different
surface treatment methods of the gray iron inserts: (a) no treatment except for being cleaned; (b) salt
membrane plating; (c) zinc barrel plating for 1 hour; (d) zinc barrel plating for 2 hours; (e) zinc barrel
plating for 3 hours; (f) zinc rack plating for 1 hour