Combustion synthesis of C/MgAl 2 O 4 composite powders using magnesium oxalate as carbon source

In order to solve the bottleneck problems including uniform distribution, and oxidation resistance of nano carbons in oxide ceramics, C/MgAl 2 O 4 composite powders were prepared with MgC 2 O 4 ·2H 2 O, MgO 2 , Al 2 O 3 , and Al as raw materials via combustion method under argon atmosphere. The maximum adding amount of MgC 2 O 4 ·2H 2 O is 34.34 wt%. The phase compositions and microstructures of combustion products were characterized through X‐ray diffraction ( XRD ), scanning electron microscope ( SEM )/ EDX , and Raman spectroscopy. The results showed that the phases of products are mainly composed of MgAl 2 O 4 and carbon. The prepared MgAl 2 O 4 has granular and rod‐like morphologies, and the free carbon (1.172 wt%) exists between particles of MgAl 2 O 4 . Moreover, the addition of FeC 2 O 4 as catalyst in raw materials ratio would be beneficial for improving crystallization of in situ carbon generated in the products. The oxidation activation energy of the prepared C/MgAl 2 O 4 composite powders was calculated as 143.01 kJ/mol which was 22.17% higher than that of carbon black/MgAl 2 O 4 powders (117.06 kJ/mol), suggesting that the C/MgAl 2 O 4 composite powders prepared by combustion synthesis have excellent oxidation resistance.