Characterization of Ni-doped pyrolyzed phenolic resin and its addition to the Al2O3–C refractories

Abstract

The catalytic graphitization of the phenolic resin was investigated in the presence of various amounts of nickel nitrate at 600–1200 °C in a reducing atmosphere for 3 h. For comparison, the effect of catalyzed phenolic resin versus none-catalyzed one was explored on the microstructure and mechanical properties of the Al2O3–C refractory specimens within a range of 800–1400 °C. The phase composition and microstructure evolution were investigated using X-ray diffraction and SEM, respectively. RAMAN spectroscopy was used to measure the graphitization level of phenolic resin. Results indicated that crystalline carbon (graphite) was achieved only from Ni-catalyzed phenolic resin at a high temperature (~1200 °C), while non-catalyzed resin led to the formation of amorphous carbon. Mechanical properties of the Al2O3–C specimens were improved due to the presence of catalyzed phenolic resin. SEM results illustrated that the enhancement was associated with the in-situ formation of the SiC phase in whisker shape in the microstructure of specimens containing Ni-catalyzed phenolic resin.