(杭州电子科技大学 机械工程学院,杭州 310018)
摘 要: 采用不同浓度的丙烷通过准稳态流化床化学气相沉积(FBCVD)工艺在1250~1450 ℃的沉积温度下产生低温各向同性热解炭(LTIC),利用SEM和TEM研究沉积温度和丙烷浓度对LTIC微观结构的影响。结果表明:沉积温度和丙烷气体浓度对低温各向同性热解炭的形貌结构有较大的影响。随着沉积温度或丙烷气体浓度的升高,各向同性热解炭形貌结构由片层状向类球形颗粒状转变,密度和织构降低,而这些变化与芳香碳平面的弯曲度发生变化有关。增大密度和提高形核率是获得性能优异各向同性热解炭的一个重要途径,沉积温度选择1350 ℃,丙烷浓度保持在25%~40%之间,所获得的热解炭结构和性能较为优异。
关键字: 低温热解炭;各向同性;沉积条件;微观结构
(School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China)
Abstract:The low temperature isotropic pyrocarbon (LTIC) was prepared by a quasi-steady-state fluidized bed chemical vapor deposition (FBCVD) at deposition temperature of 1250-1450 ℃ with propane at different concentrations. The effects of deposition temperature and propane concentration on the microstructure of the LTIC were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the deposition temperature and propane concentration have great influence on the fracture surfaces and texture of LTIC. As the deposition temperature and propane concentrations raising, the fracture surfaces of LTIC change from laminar structure to globular-like structure with decreasing the density and texture, which are correlated to variations in the tortuosity of the aromatic carbon layers. The increase of the density and nucleation rate is an important way to get isotropic pyrocarbon with excellent properties, when the deposition temperature is controlled at 1350 ℃ with 25%-40% propane concentrations, the structures and properties of LTIC are excellent.
Key words: low temperature pyrocarbon; isotropic; deposition condition; microstructure