Oxidation of Intermetallic Al–Fe–Mo Phases

Thermal oxidation processes of Al 9‐ x Fe x Mo 3 intermetallic phases are investigated by thermogravimetry, in situ X‐ray diffraction, and reactivity investigations in ambient air and under vacuum. Identified intermediate compounds are AlFe, AlMo 3 , and FeMoO 4 . The formation of Fe‐rich and Al‐rich molybdates along with Al 2 O 3 is found as the reaction products of the total oxidation. The compositions of Al 2‐y Fe y (MoO 4 ) 3 are derived from fits of the molar volumes to a Vegard law. The intermediate FeMoO 4 occurs from the reaction of AlFe with Fe 2 (MoO 4 ) 3 in vacuum.