In situ formation of carbon nanotubes and ceramic whiskers in Al2O3–C refractories with addition of Ni-catalyzed phenolic resin

Microstructure and mechanical properties of Al2O3–C refractories using Ni-catalyzed phenolic resin as binder coked in the temperature range from 800 °C to 1400 °C are investigated in the present work. The results showed that only amorphous carbon formed from as-received phenolic resin, while crystalline graphite carbons, particularly multi-walled carbon nanotubes (MWCNTs) were gradually obtained from Ni-catalyzed phenolic resin with increasing the pyrolysis temperature from 450 °C to 1050 °C. The morphology and quantity of in situ formed carbon nanotubes (CNTs) in Al2O3–C matrix specimens were closely associated with the coking temperature. The mechanical properties such as cold modulus of rupture (CMOR), flexural modulus (E), force and displacement of Al2O3–C refractory specimens with addition of Ni-catalyzed phenolic resin were greatly improved compared with those with as-received phenolic resin. The improvement was attributed to the in situ catalytic formation of CNTs and more ceramic whiskers in the specimens containing Ni-catalyzed phenolic resin.