Selective High-Temperature Oxidation of Phases in a Cast Refractory Alloy of the 25Cr – 35Ni – Si – Nb – C System
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The process of oxidation of alloy 0.45C – 26Cr – 33Ni – 2Si – 2Nb at a temperature of 400 – 1150°C in air and in vacuum (133 × 10 – 2 Pa) is studied. The content of oxygen on the surface of different phases in the structure of the alloy is determined experimentally after a high-temperature hold of different duration. The oxidation of the alloy is shown to be selective due to differences in the chemical composition of the phases in its structure. It is shown that alloys of the 25Cr – 35Ni – Si – Nb – C system are highly resistant to oxidation, which is explained by the contribution of the matrix γ-phase and chromium carbides.
Key wordscast refractory alloys microstructure phase composition high-temperature oxidation selective oxidation of phases
The authors are sincerely grateful to Professor N. M. Ryzhov of the Bauman Moscow State Technical University for the valuable criticism and helpful and benevolent discussion of the work and to S. N. Petrov and M. D. Fuks of the “Prometey” Central Research Institute of Composite Materials for the participation in the experiments.
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