Magnetron Sputtered NbN Films with Nb Interlayer

NbN films were deposited on SS substrates by reactive DC magnetron sputtering at various N2 flow rates and substrate biasing. Effect of N2 flow rate and substrate biasing has been studied on deposition rate, surface hardness, crystal-structure and adhesion values. Process parameters were optimized for deposition of NbN coatings. NbN coatings were then deposited on to MS substrates as such and with Nb interlayer deposited by magnetron sputtering. The thickness of interlayer was 2 \mum. The duplex coating has been studied for the improvement with respect to surface hardness by Knoop micro indentation and corrosion performance by potentiodynamic polarization technique. Open circuit potentials were also measured.