Nanostructured chromium coatings with enhanced mechanical properties and corrosion resistance

• High ion flux bombardment leads to a grain size reduction in MPPMS Cr coatings.
• The grain size reduction was enhanced by increasing the target current density.
• Nanocrystalline Cr coatings with gain size less than 15 nm.
• Significantly increased mechanical properties and good corrosion resistance.

Nanocrystalline chromium coatings were deposited by modulated pulsed power magnetron sputtering (MPPMS) at different peak target current densities. The substrate current density increased as the peak target current density was increased. The columnar grain structure of the Cr coatings gradually evolved to randomly oriented nanocrystallites with grain sizes less than 15 nm by increasing the peak target current density to 1.2 Acm− 2. The nanocrystalline Cr coatings showed a 267% increase in the hardness to 16 GPa and higher corrosion resistance as compared to the coating deposited by conventional dc magnetron sputtering.