Facile preparation of superhydrophobic carbon nanotube coated MgO-CaO grains via densified micro-zone deposition for high-performance MgO-CaO-C refractories
Hang Li, Ling Zhang, Zhong Huang, Shaowei Zhang, Haijun Zhang
Abstract
Carbon nanotube (CNT) modified MgO-CaO particles (C-MCPs) were synthesized for the first time via a novel and facile densified micro-zone deposition (MZD) method. The effects of temperature, polyethylene (PE) content, catalyst concentration, and forming pressure on the structure, properties, and performance of the C-MCPs were systematically investigated. The optimal synthesis conditions were identified as a temperature of 700°C, a PE powder addition of 20 %, a catalyst concentration of 0.75 wt%, and a forming pressure of 5 MPa. Under these conditions, the resulting C-MCPs exhibited excellent superhydrophobicity with a maximum water contact angle (WCA) of 157°, and the hydration weight gain of as-prepared C-MCPs is only 8.3 wt%, which is 50 % lower than that of raw MgO-CaO grains. The addition of C-MCPs in unburned ultralow carbon MgO-CaO-C refractories can greatly decrease their hydration weight gain by 52 %. The MZD strategy is also efficient for fabricating CNTs coated Al 2 O 3 , MgO and MgAl 2 O 4 grains, offering a promising and scalable route for the preparation of CNTs containing refractory precursors.