结合中间相沥青的热性能和微型气泡的受力行为,通过比较不同原料体系所制泡沫炭的孔结构差异,研究了泡沫炭在自发泡过程中的成核行为。结果表明:1)中间相沥青在发泡过程中最初生成的气体将成为泡核,随后生成的微型气泡将在表面能及气泡内外压差的驱动下,在泡核周围逐步进行兼并、聚集和膨胀,并在表面张力作用下成为球形气泡;2)自发泡过程中,中间相沥青的热性能是影响成核行为和泡沫炭孔结构均一性的主要因素。
Carbon foams were prepared with self-bubbling method using mesophase pitch(MP) as carbon precursor.The nucleation behaviors were proposed according to the thermal performance of MP,force analysis of micro-bubble and pore structures of carbon foam.Results indicate that when MP is heated to a certain temperature,the earliest produced gases serve as the nucleation sites,and then the subsequent produced micro-bubbles will segregate,aggregate and expand around the nuclei,forming spherical bubbles under the force of surface tension.The thermal performance of MP will play a crucial role in the nucleation and homogenicity of pore structures.