论文部分内容阅读
研究以单质硅粉(Si)、金属铝粉和硅粉的混合物(Al+Si)作为2种不同硅源时,在埋碳床中经1000～1500℃处理后多壁碳纳米管(multi-walled carbon nanotubes,MWCNTs)表面涂层的形成及其抗氧化性能的变化。采用X射线衍射仪、高分辨透射电镜及能谱仪和热重-差示扫描量热仪对处理前后的样品进行表征。结果表明:以Si为硅源时,MWCNTs经小于1400℃处理后表面生成了SiC涂层,1500℃处理后大部分MWCNTs蚀变成实心的SiC纳米线;与Si相比,以Al+Si为硅源时相同温度处理后MWCNTs表面涂层的厚度增加,且1500℃处理后MWCNTs并未发生结构蚀变。与原MWCNTs相比,处理后的MWCNTs抗氧化性能提高,且随着涂层厚度的增加而不断提高。非等温动力学进一步表明,原MWCNTs的氧化活化能为157.69kJ/mol,以Si为硅源时1400℃处理后为202.39kJ/mol,而Al+Si为硅源时达到230.70kJ/mol。
The effect of multi-walled carbon nanotubes (CNTs) on the surface morphology of multi-walled carbon nanotubes (CNTs) walled carbon nanotubes (MWCNTs) surface coatings and their oxidation resistance changes. The samples before and after treatment were characterized by X-ray diffraction, high-resolution transmission electron microscopy and energy dispersive spectroscopy and thermogravimetry-differential scanning calorimetry. The results show that when Si is used as the silicon source, the SiC coating is formed on the surface of the MWCNTs after being processed at less than 1400 ° C, and most of the MWCNTs after solidification at 1500 ° C are transformed into solid SiC nanowires. Compared with Si, The thickness of the MWCNTs surface coating increased with the same temperature on the silicon source, and there was no structural alteration of the MWCNTs at 1500 ℃. Compared with the original MWCNTs, the oxidation resistance of treated MWCNTs increased, and with the increase of the thickness of the coating increasing. The non-isothermal kinetics further shows that the oxidation activation energy of the original MWCNTs is 157.69kJ / mol, which is 202.39kJ / mol at 1400 ℃ when Si is the silicon source, and 230.70kJ / mol when Al + Si is the silicon source.