采用微正压CVD法制备块体各向同性热解炭

Preparation of bulk isotropic pyrocarbons by micro-positive CVD

以丙烯作为碳源气体,氮气和氢气作为载气和稀释气体,采用自行设计的化学气相沉积(CVD)炉,设计特殊的发热体,利用微正压化学气相沉积法制备块体各向同性热解炭材料。对制备的材料取样分析,利用排水法测量样品的表观密度;通过金相显微镜表征材料的组织结构和表面形貌;利用扫描电子显微镜(SEM)和透射电子显微镜表征材料的微观结构和断口特征。提出了一种新的各向同性热解炭的沉积机理即电磁场流态化沉积机理。研究结果表明:在1 000～1 300℃沉积10～40 h,可得到密度为1.73～1.93 g/cm3、厚度为5～15 mm的各向同性热解炭材料块体,主要由球形颗粒状热解炭组成,结构致密,孔隙较少,分布均匀,热解炭颗粒之间产生融并现象。

Bulk isotropic pyrocarbon materials were prepared by micro-positive chemical vapor deposition（CVD） with self-designed CVD furnace,using propylene as carbon source gas,nitrogen and hydrogen as carrier gas and dilution gas.The density of isotropic pyrocarbons was measured by water displacement method.The microstructure and surface morphology as well as fracture characteristics of isotropic pyrocarbons were studied by polarized light microscope,scanning electron microscope and transmission electron microscope,respectively.A new deposition mechanism of isotropic pyrocarbons-electromagnetic field fluidization deposition mechanism was proposed.The results show that the bulk isotropic pyrocarbons which are fabricated in 10-40 h,at 1 000-1 300 ℃,are mainly composed of the spherical pyrocarbon granules.With density of 1.73 to 1.93 g/cm3,and thickness of 5 to 15 mm,it has compact structure and few pores.Most of the spherical pyrocarbon granules are congrutinated with each other.