Ablation behaviors of Ir[sbnd]Al intermetallic coatings in a plasma wind tunnel.

The ablation behaviors of an as-annealed aluminized Ir (IrAl/Ir) coating sample and two aluminized Ir (IrAl 2.7(3) /IrAl/Ir) coating samples were investigated in a plasma wind tunnel for up to 2000s. The IrAl/Ir and IrAl 2.7(3) /IrAl/Ir coating samples showed quite different thermal responses, with ablation resistance limits of ~3.35 MW/m2 and ~3.75 MW/m2, respectively, due to their different oxidation mechanisms. The failure mechanisms of both Ir Al intermetallic coating samples were closely related to the melting of Al 2 O 3 coating due to over-temperature. The results indicated that the Ir Al is a promising non-ablative thermal protection coating material used in non-equilibrium oxidizing environment up to 2000 °C. Unlabelled Image • The ablation resistance of Ir Al coating was investigated in a plasma wind tunnel. • Ir Al intermetallic coating is a non-ablative coating for up to 2000 °C. • The oxidation mechanism of Ir Al coating is determined by the contents of Al. • The failure of Ir Al coating is resulted from the melting of Al 2 O 3 coating. [ABSTRACT FROM AUTHOR]