대향류 확산화염을 이용한 친환경 선박용 소재인 탄소나노튜브의 합성에 관한 연구

Abstract

Carbon nanotubes(CNTs) have potential in fields such as space transportation, nanotechnology, electronics, optics, materials science, and architecture since they have unique and useful chemical and physical properties, extraordinary strength, and efficiency in heat conduction. Numerous techniques have been developed for the synthesis of CNT, including Electric discharge, Laser ablation, chemical vapor deposition etc.

But these methods require high energy input and difficulty in separating CNTs from the product. Therefore, large-scale applications require a simple, continuous and energy efficient method to synthesis CNTs. Recently, Flame synthesis method has attracted considerable attention due to energy efficiency, large scale synthesis & high purity synthesis of CNTs.

In this study, experimental studies were performed for the synthesis of Carbon Nano Tube using Counterflow diffusion flame which can be used as a material of Eco-Ship. Methane with Hydrogen & Acetylene were used as a fuel gas and errocene was used as a catalyst for synthesis of CNT.

These major parameters were H₂& C₂H₂ mixing rate as a fuel gas and N₂& Ar gas mixing rate as dilution gas in fuel side. Characteristics of CNT formation were analyzed from SEM(Scanning Electron Microscope) & TEM(Transmission Electron Microscope). As the result of these works, First, as shown in numerical result, the flame temperature was increased with increasing hydrogen concentration. The temperature of 10% H₂mixture flame was higher 150 K than pure H₂flame. This means that the temperature plays an important role for synthesis of CNT. Second, in case of using Argon as a dilution gas, the flame temperature was increased about 100 K and found out various CNTs which have thicker diameter & longer length. Third, In case of using CH₄and C₂H₂as fuel gas, due to increase in carbon source and flame temperature, acceleration of synthesis of CNT was found. Result from increasing of flame temperature, diameter of CNT became thick but the length became short. According to the CNT mechanism, it can be considered that the excessive carbon source is growing as soot and pollute catalyst particle and then they interrupts supply of carbon source.

Accordingly, it was found that the supply of appropriate quantity of carbon source can makes effect to synthesis of high purity of CNT.