Abstract:
Advanced ternary (Ti,Al)N coatings were produced
by reactive magnetron co-sputtering with a 300
magnetron configuration. The results reflected the
significance and complexity of the nitrogen
pressure effect on the coating development. As the
nitrogen pressure increased above 0.4 mTorr, a
transition of the coating structure from densified,
fine columnar grains to porous faceted grains
occurred, resulting in an abrupt decrease of the
coating hardness. It is believed that an increase of
the nitrogen pressure to high values may cause
serious collision and scattering of the depositing
atoms and poisoning of the targets, thus resulting in
significantly fewer atoms/molecules arriving at the
substrate with much lower energies. The adatom
mobility and the nucleation rate in the coatings are
therefore greatly reduced, resulting in development
of a coarse grained structure.
