Compositions involving CR2-O3V2O3-TiO2

This patent describes a method of preparing a composition from Cr2O3, V2O3 and TiO2 wherein the composition falls within the shaded area circumscribed by ABCDF as shown in the disclosed FIGURE. It comprises heating V2O5 powder having a particle size of less than about 50 microns in an atmosphere in which the partial pressure of oxygen is in the range of 10-8 to 10-10 atmospheres while starting at a temperature of 600 degrees C and gradually increasing the temperature over a period in the range of about 12 to 24 hours to about 1300 degrees C for a period to ensure complete reduction of all vanadium to V3+; separately heating TiO2 and Cr2O3 powders each having a particle size of less than about 50 microns for a period of about 10 to 14 hrs at a temperature in the range of about 600 degrees C to 800 degrees C for TiO2 and about 1000 degrees C to 1200 degrees C for Cr2O3; thoroughly grinding together about 35 to 98 wt. % of V2O3 from, with about 0 to 55 wt. % of TiO2 and about 2 to 45 wt. % of Cr2O3 to produce a mixture having a grain size of less than about 50 microns; pelletizing the mixture at a pressure of about 5,000 psi; and heating and reacting together the pellets at a temperature in the range of about 1100 degrees C to 1800 degrees C for a period in the range of about 1/2 to 48 hrs in an atmosphere in which the partial pressure of oxygen is in the range of 10-10 to 10-5 atmosphere. This patent also describes composition produced from Cr2O3, V2O3 and TiO2, wherein the composition is a solid solution