Abstract:
Ternary chromium aluminium nitride (Cr,AI)N coatings were produced by reactive
magnetron co-sputtering technique at different nitrogen deposition pressures. Densified
nanostructured coatings with grain size below 100 nm were obtained under critically controlled
deposition conditions at low nitrogen partial pressures. The nanostructured coatings were generally
of improved surface roughness and properties. Microhardness measurements showed that the
coatings had much higher hardness than those of coarser grain sizes. It is believed that the
refinement of the coating structure at low nitrogen pressures is associated with a larger number of
atoms/molecules depositing on the substrate with higher energies, thus enhancing the adatom
mobility and nucleated cluster formation in the coatings. The relationship between the grain size
reduction and the deposition rate of the coatings was analysed.
