Duplex surface treatment of high strength Timetal 550 alloy towards high load-bearing capacity

In the present investigation, novel duplex systems combining nickel diffusion (ND) deep case hardening with low friction wear resistant TiN and diamond-like carbon (DLC) coatings have been designed and applied to high strength Timetal 550 titanium alloy. The load bearing capacity of the duplex treated Timetal 550 was assessed dynamically using both a scratch tester and an Amsler tribometer with a block-on-wheel configuration. Experimental results showed that the load bearing capacity of these low friction wear resistant coatings can be improved dramatically when deposited on ND-treated Timetal 550 substrate relative to material coated with TiN and DLC alone. It was also found that the DLC/ND duplex system possessed superior load bearing capacity to the TiN/ND duplex system.