Carbon Co-Deposition During Gas Reduction of Water-Atomized Fe-Cr-Mo Powder

The water atomization of iron powder with a composition of Fe-3Cr-0.5Mo (wt.%) at 1600°C and 150 bar creates an oxide layer, which in this study was reduced using a mixture of methane (CH ) and argon (Ar) gas. The lowest oxygen content was achieved with a 100 cc/min flow rate of CH , but this also resulted in a co-deposition of carbon due to the cracking of CH . This carbon can be used directly to create high-quality, sinter hardenable steel, thereby eliminating the need for an additional mixing step prior to sintering. An exponential relationship was found to exist between the CH gas flow rate and carbon content of the powder, meaning that its composition can be easily controlled to suit a variety of different applications.