Sputter-coating of Ti-6Al-4V with inconel 617 for erosion resistance

Abstract

Inconel 617 and reactively sputtered Inconel 617 nitride coatings 26 – 28 μm thick were magnetron sputtered onto glass and titanium substrates at 1900 Å min−1 and 1400 Å min−1 respectively, and then characterized. Sputtered Inconel 617 coatings are smooth, adherent and ductile, with a b.c.c. structure. Equiaxed grains ranging in size from 300 to 1000 Å in diameter were found. Nitrided Inconel 617 is brittle, adherent, and has a two-phase structure consisting of fine crystallites, tentatively identified as f.c.c. Ni4N, embedded in a semicrystalline matrix, and was found to be 38% harder than the non-nitrided coating. Sputtered Inconel 617 could not be compared with the Thornton zone model, but the nitrided coating corresponded well to a Zone T structure. Coatings deposited on Ti-6Al-4V were eroded at 90° with 15 μm SiC at a velocity of 67 m s− in order to examine the mechanisms of erosion. Both coatings exhibited ductile mechanical behavior at single impact sites. The cutting mechanism was prevalent. Embedded and fragmented erodent was also found.