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

摘要

The catalytic graphitization of the phenolic resin was investigated in the presence of various amounts of nickel nitrate at 600-1200 degrees 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 degrees 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 (similar to 1200 degrees 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.