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

Abstract

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.