Combustion Synthesis of Metal Chromite Powders

Abstract

Fine‐particle metal chromites (MCr 2 O 4 , where M = Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn) have been prepared by the combustion of aqueous solutions containing the respective metal nitrate, chromium(III) nitrate, and urea in stoichiometric amounts. The mixtures, when rapidly heated to 350°C, ignite and yield voluminous chromites with surface areas ranging from 5 to 25 m 2 /g. MgCr 2 O 4 , sintered in air at 1500°C for 5 h, has a density of 4.0 g/cm 3 .