Preparation of porous Cr3C2 grains with Cr2O3

Porous Cr3C2 grains (similar to 300 to 500 mu m) with similar to 10 wt% of Cr2O3 were prepared by heating a mixture of MgCr2O4 grains and graphite powder at 1450 degrees to 1650 degrees C for 2 h in an Al2O3 crucible covered by an Al2O3 lid with a hole in the center. The porous Cr3C2 grains exhibited a three-dimensional network skeleton structure. The mean open pore diameter and the specific surface area of the porous grains formed at 1600 degrees C for 2 h were similar to 3.5 mu m and similar to 6.7 m(2)/g, respectively. The present work investigated the morphology and the formation conditions of the porous Cr3C2 grains, and this paper will discuss the formation mechanism of those grains in terms of chemical thermodynamics.