Heat resistance of metal-intermetallic compositions based on NiAl

Heat resistance of the intermetallic compound NiAl, its alloys with Hf and Nb, and composition materials with a microhoneycomb structure (tungsten honeycombs with a wall thickness of 0.3-3 μm and a core of NiAl or the NiAl-4 at% Nb alloy) are investigated. The oxidation rate (w ^sup +^) is calculated by the weight increment from oxidation in air at t = 1000-1300°C for τ ≤ 21 h, and the rate of burning loss (w ^sup -^) is calculated by the weight loss during removal of the scale. NiAl and its alloy have the minimal oxidation rate: 4.4 wt % Hf (w ^sup +^ = 4.5-20 g/(m^sup 2^ h) at 1200°C). Resistance to scaling of NiAl composites of (13-44) at% W(Mo) is much lower than that of the NiAl intermetallic compound. The higher the content of refractory metal, the lower the resistance to scaling. It depends weakly on the method of compositing of the material (honeycomb structure NiAl-W or mixture of the grains of NiAl and W with sizes of 10-20 μm); however, short-term heating of a composite with a honeycomb structure (13% W, layer 0.5 μm) to 1200-1300°C (above the test temperature) can reduce the rate of subsequent oxidation at t = 1000°C by a factor of 200, and at t = 1100°C by a factor of 30.[PUBLICATION ABSTRACT]