Magnetron Sputtered NbN Films with Nb Interlayer on Mild Steel
Figure 10
Scratch test for NbN coating (deposited at N2/Ar flow = 20%) on MS with Nb interlayer at (a) 1 N, showing start of the scratch, (b) 12 N, revealing segregation, cracks, and pores, (c) 22 N, displaying cracks, pores, and pile-up, and (d) 32 N, showing chipping, pile-up, and partial delamination.