Catalytic formation of one-dimensional nanocarbon and MgO whiskers in low carbon MgO-C refractories

Low carbon MgO-C refractories added with a Ni-containing catalytic precursor and Al were prepared. MgO-NiO composite powder was firstly prepared by mixing magnesia powder in nickel nitrate ethanol solution and then incorporated into MgO-C refractories after pre-treating. The phase composition, microstructure and mechanical properties of MgO-C refractories treated at 1000 °C and 1400 °C were investigated by means of X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and three-point bending test. The results showed that the addition of the Ni-containing catalytic precursor promoted the formation of one-dimensional nanocarbon at 1000 °C and the growth of MgO whiskers at 1400 °C, respectively. The in situ formation of MgO whiskers enhanced the mechanical properties of MgO-C refractories after coking at 1400 °C, which showed higher cold modulus of rupture and much larger displacement than MgO-C refractories without addition of the Ni-containing catalytic precursor.