Reduction of surface oxide layers on water-atomized iron and steel powder in hydrogen: Effect of alloying elements and initial powder state
Journal article, 2020

The reduction of surface oxide layers covering commercial water-atomized iron and steel powder grades have been investigated using model thermogravimetric reduction cycles in hydrogen. The influences of powder composition and initial condition on the oxide reduction were studied for three powder grades and compared to Fe2O3. Isothermal and dynamic measurements were conducted to assess the reduction progress and kinetic analyses were then used to calculate the apparent activation energies of reduction. Chromium-alloyed powder showed significantly lower activation energies compared to iron powder and Fe2O3, likely originating from the presence of Cr oxide in the oxide layer. The reduction was also found to be strongly affected by the initial state of the oxide layer which reflects the powder production. Surface analysis by X-ray photoelectron spectroscopy (XPS) showed a progressive increase in Cr with gradual reduction of the oxide layer, indicating its presence and possible involvement in the oxide reduction.

thermogravimetric analysis

oxide reduction

water-atomized iron powder

reduction kinetics

water-atomized steel powder

Author

Johan Wendel

Chalmers, Industrial and Materials Science, Materials and manufacture

Swathi Kiranmayee Manchili

Chalmers, Industrial and Materials Science, Materials and manufacture

Eduard Hryha

Chalmers, Industrial and Materials Science, Materials and manufacture

Lars Nyborg

Chalmers, Industrial and Materials Science, Materials and manufacture

Thermochimica Acta

0040-6031 (ISSN)

Vol. 692 1-10

Nanotechnology Enhanced Sintered Steel Processing

Swedish Foundation for Strategic Research (SSF), 2016-01-01 -- 2020-12-31.

Areas of Advance

Production

Subject Categories

Metallurgy and Metallic Materials

DOI

10.1016/j.tca.2020.178731

More information

Latest update

9/4/2020 8