Processing and Characterization of Multi-Walled Carbon Nanotubes Containing Alumina-Carbon Refractories Prepared by Nanocomposite Powder Technology

Carbon nanotubes (CNTs) have often been used as additives to improve the properties of refractories containing carbon. However, it is very difficult to evenly distribute CNTs in the matrix. In order to solve this difficulty, an alumina/multi-walled carbon nanotube (MWCNT) (AM) composite powder in which MWCNTs had grown on the surfaces of Al₂O₃ particles was developed and used in alumina-carbon (Al₂O₃-C) refractories. The effects of the AM composite powders on the microstructure and properties of the Al₂O₃-C refractories were studied and compared with the commercial MWCNTs. The nanocomposite powders significantly improved the distribution uniformity of MWCNTs in the Al₂O₃-C matrix. The densification, fracture properties, thermal shock resistance, and slag corrosion resistance were enhanced due to the well-dispersed MWCNTs. On the contrary, no improvement of the densification, fracture properties, and thermal shock resistance of the refractories was achieved by addition of commercial MWCNTs due to the agglomeration of MWCNTs.