Improved properties of low‐carbon MgO‐C refractories with the addition of multilayer graphene/MgAl ₂ O ₄ composite powders

Abstract

Abstract The paper investigated the effects of different amounts (0%, 3%, 6%, 9%) of in situ multilayer graphene/MgAl 2 O 4 composite powders on the slag resistance, thermal shock resistance, and oxidation resistance of low‐carbon MgO‐C refractories. Comparing with commercial MgAl 2 O 4 , the MgAl 2 O 4 in in situ multilayer graphene/MgAl 2 O 4 composite powders has higher lattice strain of crystal, which can trap more Mn and Fe ions, resulting in the better slag resistance. The oxidation decarbonation layer of MgO‐C specimen with 3% composite powders is 9.71 mm, which is lower than not only the specimen with other contents but also specimen containing carbon black/MgAl 2 O 4 powders. Moreover, the residual strength ratio of the specimen C/MA‐3 was 47.47%, which is 28.5% and 8.08% higher than specimens with no additive and with carbon black/MgAl 2 O 4 powders, respectively. Both improving thermal shock and oxidation resistance properties are related with the unique nano structure, multilayer graphene in situ formed between MgAl 2 O 4 grains, of added composite powders. The former is due to higher strain energy consumed by multi‐deflection of cracks inside the multilayer graphene/MgAl 2 O 4 composite powders. And the latter is due to the higher energy of oxidation activation of multilayer graphene/MgAl 2 O 4 composite powders due to effective protection of multilayer graphene by MgAl 2 O 4 .