Development of high oxidation resistant coating of nanostructured MgO on carbon nanotubes via simple precipitation technique in Mg/CO gas system

The synthesis of oxide-coated carbon nanotubes (CNTs) by a simple precipitation reaction in Mg/CO gaseous system was studied. The results showed that nanostructured MgO could be uniformly coated on the surface of CNTs via inhomogeneous Mg(g) and CO(g) precipitation reaction. Furthermore, we have developed a mixing procedure based on simultaneous agitation and ultra-sonication in order to break CNT bundles and prepare highly dispersed starting materials. By applying such mixing procedure, dispersed and distinct nano-oxide coated CNTs were synthesized which can be efficiently utilized in different composite matrices. Oxidation resistance of samples was investigated by DSC/TG thermal analysis. The results showed that oxide-coated CNTs present superior resistance against oxidation even at rather elevated temperature of 1000 °C and total weight loss of coated CNTs was measured to be less than 1 wt% during heat treatment at such temperature. Finally, coating adhesion was evaluated employing ultrasonic waves (as mechanical force) and subsequent weight loss measurement at temperature of 1000 °C.