(Ti,Cr)N nanolayer coatings were deposited on Ti-6Al-4V, 17-4PH and Inconel 718 substrates using cathodic arc physical vapor deposition for improved erosion and corrosion resistance. Coating corrosion performance was highly dependent on the coating thickness and packing factors and correlated with increased chromium content within the (Ti,Cr)N nanolayer coatings. The change in cathode current predominantly affected coating thickness and the bias affected the packing factor. Erosion tests of the coated and uncoated substrates at both 30° and 90° erodent impingement angles were conducted using angular aluminum oxide media at particle velocities up to 145 m/s. Chromium evaporator current and substrate bias were varied to change film stoichiometry and microstructure for erosion performance evaluation. When chromium evaporator current was varied, the increase in chromium content led to an increase in binary CrN phase volume and a decrease in TiN phase volume. The increase in CrN phase volume decreased both hardness and erosion performance at both impingement angles. Lower bias values resulted in better erosion performance. At 30° erodent impingement, all coated samples outperformed the uncoated substrate; whereas, for 90° impingement, only coatings deposited at low bias values (- 25 V, - 50 V, and - 100 V) and high Ti:Cr ratios (>. 2.4) outperformed the uncoated substrate. The primary coating failure mechanism was microchipping.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry