Thermophysical properties and deposition of B2 structure based Al–Ni–Ru–M alloys

The thermophysical properties of B2 structure based Al–Ni–Ru–M alloys have been studied for different alloy compositions. A normal value for the thermal conductivity of these alloys is within the range of 10–20 W m−1 K−1 range at room temperature, but can be reduced to approximately 3.5 W m−1 K−1 by modifying the alloy composition. The observed positive and approximately linear temperature dependence of the thermal conductivity of B2 structure based on Al–Ni–Ru–M alloys indicates their metal electronic nature. l expansion coefficients (i) increase with temperature, (ii) are similar to those of superalloys and steels, and (iii) are mostly dependent on Ru content. A fused and subsequently pulverized Al–Ni–Ru B2 alloy was deposited on a Ni-based superalloy substrate made of modified CMSX-4 using vacuum and atmospheric plasma spraying. The coatings obtained were characterized for their microstructure, phase composition, hardness, and bond strength. The coatings exhibited sound microstructural integrity and favorable coating–substrate adhesion. The phases originally present in the powder were also found to be retained in the coating. Interdiffusion processes between the investigated coatings and the Ni-based superalloy substrate were primarily estimated by the diffusion couples approach. The segregation of a new intermetallic phase was detected at the (Al50Ni40Ru10 alloy)/(modified CMSX-4) interface.