Study of phase states and oxidation of B2-structure based Al-Ni-Ru-M alloys

Protective α-Al2O3 scale develops already after 100-150 h of oxidation. The protective α-Al2O3 scale (i) is mono-phased (α-Al2O3), (ii) is dense, (iii) does not contain remarkable amount of Ni and Ru and (iv) has good adhesion to bulk alloy. A dense continuous Ru underlayer forms between the α-Al2O3 film and the bulk alloy for compositions with Ru>25 at.%. The Ru layer can contain considerable amounts of Cr or Ir and exhibits good adhesion to both the scale and the bulk alloy. Physical properties of the B2 structure based Al-Ni-Ru-M alloys make them good candidates for oxidation resistant coatings in different high temperature industrial applications.