Tribological investigation of TiAlCrN and TiAlN/CrN coatings grown by combined steered-arc unbalanced magnetron deposition

The dry sliding wear of monolayer TiAlCrN and multilayer TiAlN/CrN coatings has been investigated against a BM2 tool steel counterface. The coatings w ere deposited on a BM2 tool steel substrate by combined steered-arc/unbalan ced-magnetron deposition. Increasing either contact load or sliding speed l ed to a reduction in friction coefficient, typically from 1.1 to 0.2. Incre asing load resulted in an increase in wear rate for both TiAlCrN and TiAlN/ CrN (e.g. from 7 x 10(-6) mm(3)/m at 22 N to 4 x 10(-5) mm(3)/m at 189 N fo r the TiAlCrN monolayer coating, and from 7 x 10(-6) mm(3)/m at 22 N to 2.5 x 10(-5) mm(3)/m at 189 N for TiAlN/CrN multilayer). The wear rate for all coatings was at least an order of magnitude lower than the uncoated BM2 st eel. The wear rate of the TiAlCrN coating tended to decrease with an increa se in sliding speed (from 7.4 x 10(-5) mm(3)/m at 0.2 m/s to 1.3 x 10(-5) m m(3)/m at 1.1m/s) while the wear rate of the TiAlN/CrN was approximately co nstant as a function of sliding speed (similar to 1.5 x 10(-5) mm(3)/m). (C ) 1999 Elsevier Science Ltd. All rights reserved.