Papers by Keyword: Carbon Nanotube (CNT)

Abstract: Finite element modelling of a magnesium alloy matrix filled with a 2% volume fraction of carbon nanotubes (CNT) under 2.45 GHz microwave (MW) irradiation is reported. The effective dielectric and permeability data of the simulated compact are evaluated using the effective medium approximation. Subsequently, these values are used to solve Maxwell’s electromagnetic equations followed by the heat conduction equation, thus both the field distribution in the oven cavity and the predicted heating of the model compact are obtained. At an applied power of 1 kW and a 9-minute simulation time, the results show poor coupling between the monolithic metal compact and the MW, resulting in a maximum temperature of ~163 °C. It is in good agreement with earlier studies and theory in which metals did not couple very well with MWs at room temperatures. The model also predicts the temperature in the 2% CNT-filled alloy compact to be 13 °C higher than in the monolithic compact after a similar simulated microwave irradiation duration. Furthermore, the effect of susceptor-assisted microwave heating is investigated by introducing a susceptor kiln into the model. Simulation results predict the temperature of the compact to rise to about 600 °C after 9 minutes, highlighting the importance of susceptor-assisted sintering. The model developed is significant in providing important details for predicting the response of metal compacts and their composites to MW heating as well as further improving the development of MW technology for the production of materials with enhanced properties.

Abstract: Mechanism of CNT-metal bonding is investigated using molecular dynamics in this study. Both bonding and debonding process are considered. It is shown that the bonding can be achieved at a temperature lower than the melting point. The surface melting and capillary wetting dominate the bonding process. In addition, there are two potential failure positions, one is at CNT-Ni interface and the other is at nickel surface which are determined by the strength competition of these two interfaces. To obtain high bonding strength we should form coalescence structure between CNT and the metal at a higher temperature to achieve larger contact length. Also we find that the debonding process experiences elastic deformation followed by debonding at CNT-Ni or Ni–Ni interface.