Fabrication and oxidation behavior of Cr2AlC coating on Ti6242 alloy

An similar to 5 mu m Cr2AlC coating was synthesized on near-a titanium alloy Ti6242 using an industrially sized magnetron sputtering coater. Isothermal oxidation at 700 degrees C and 800 degrees C, and cyclic oxidation at 700 degrees C of the bare alloys and coated specimens were investigated in air. The results indicated that the Ti6242 alloy faced serious oxidation problems at 700 degrees C and 800 degrees C. Repeated formation and spallation of the multilayered oxide scale on the Ti6242 alloy occurred during oxidation testing. The coated specimens exhibited much better oxidation behaviour as compared to the bare alloy. A continuous Al-rich oxide scale formed on the coating surface during the initial oxidation stages. The oxide scale and coating itself acted as diffusion barriers blocking the further ingress of oxygen and protected the substrate alloy from oxidation. The oxidation mechanisms of the bare alloy and the coated specimens were investigated based on the experimental results. (C) 2010 Elsevier BM. All rights reserved.