Nanocrystalline oxide dispersion strengthened （ODS） ferritic steel powders with nominal composition of Fe-14Cr-3W-0.3Ti-0.4Y2O3 are synthesized using sol-gel method and hy- drogen reduction. At low reduction temperature the impurity phase of CrO is detected. At higher reduction temperature the impurity phase is Cr2O3 which eventually disappears with increasing reduction time. A pure ODS ferritic steel phase is obtained after reducing the sol-gel resultant products at 1200℃ for 3 h. The HRTEM and EDS mapping indicate that the Y2O3 particles with a size of about 15 nm are homogenously dispersed in the alloy matrix. The bulk ODS ferritic steel samples prepared from such powders exhibit good mechanical performance with an ultimate tensile stress of 960 MPa.
W-Cr-C coatings with different chromium contents （0-3wt.%） were fabricated on the tungsten substrates by spark plasma sintering （SPS） method from the graphite and chromium mixed powders. SEM and XRD were exploited to analyze the effect of Cr contents on the microstructure of coatings. It was found that the abnormal hollow WC grains disappeared with addition of Cr less than 2%, and the microstructures were largely refined and densified. With further increase of Cr addition, the grains changed slightly but the densificaUon was reduced. The most dense coating was achieved at I wt.% Cr. Corrosion behavior of the W-Cr-C coatings were investigated by impedance spectrum and potentiodynamic polarization tests. Results suggested that the W-1Cr-C coated W sample exhibited the lowest corrosion current density and highest corrosion potential due to the most densified microstructure, indicating that the addition of Cr at 1 wt.% was optimal for WC coating against corrosion.
