Microstructure and tribological behavior of stripe patterned Ti0.6Al0.4N thin coatings prepared by masked deposition

Stripe patterned Ti0.6Al0.4N thin coatings were prepared by masked deposition. Surface morphology, microstructure and nanohardness of the coatings were characterized and their tribological behavior under the dry friction condition was studied. Effects of the surface patterning on the coating microstructure and tribological behavior were investigated. Results show that the surface patterning of coatings favored the spinodal decomposition of the metastable (Ti,Al)N phase into the Ti- and Al-rich (Ti,Al)N phases because the space between the coating stripes could relieve the coherency strain energy. And as a consequence, the preferred orientation was changed from (200) for the full coating to (111) for the patterned coatings. The grain size of the patterned coatings decreased, which might be due to the low deposition temperature caused by the reduced coating area which suffered the bombardment of the ions. The changes in microstructure resulted in the slight increase of the nanohardness of the patterned coatings. Both the frictional coefficient and wear volume of the patterned coatings were lower than those of the full coating and decreased as the distance between the coating stripes increased. The improved tribological behavior of the surface patterned coatings is related to the modification of coating microstructure and the effect of surface patterns.