GAS-METAL REACTIONS WITH IRON- AND NICKEL-BASE HEAT RESISTANT ALLOYS An Interpretive Literature Survey

摘要

Addition of small amounts of chromium to nickel accelerates oxidation by increasing the density of defects and enhancing diffusion in the oxide scale.nSmall additions of an element with a strong oxygen affinity increases internal oxidation of iron- and nickel-base alloys. Binary alloys of nickel with less than 4% aluminum or 10% chromium oxidize internally.n3. When present in sufficient quantities, chromium and aluminum retard oxidation of iron- and nickel-base alloys by oxidizing preferentially and forming an adherent, protective, oxide film.n4. The Fe-Cr-Al alloys appear to have sufficient corrosion resistance in most atmospheres at temperatures to 1000 C (1850 F).n5. The nickel-base superalloys retain a reasonable portion of their room temperature mechanical strength and resist the effects of oxidizing atmospheres at temperatures of 900-1200 C.n6. The life of iron- or nickel-base, heat-resistant alloys when used as thin sheet may be limited in high temperature oxidizing atmospheres.