Oxidation Behavior at 900°C of Austenitic,Ferritic, and Duplex Stainless Steels Manufactured by Powder Metallurgy

This study examines the resistance to cyclic oxidation at 900°C of two commercial P/M stainless steels—one austenitic (AISI 316L), the other ferritic (AISI 434L)—and of three duplex stainless steels of different compositions. The test results show that the porosity of these materials leads to notable differences between their high-temperature oxidation behavior and that of conventional stainless steels of similar composition. In the case of P/M materials, the resistance to oxidation and the chemical composition of the oxides formed are strongly influenced not only by the degree of porosity of each material, but also by the concentration of Ni in the base metal. In the conditions adopted in the study, ferritic stainless steel was found to provide the best high-temperature oxidation resistance.