Microstructures and formation mechanism of headstand pyrocarbon cones developed by electromagnetic-field-assisted CVD
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China)
2. College of Materials Science and Engineering, Hunan University, Changsha 410082, China)
Abstract: Novel headstand pyrocarbon cones (HPCs) with hollow structure were developed on the surfaces of pyrocarbon layers of the carbon/carbon (C/C) composites at 650-750 °C by the electromagnetic-field-assisted chemical vapor deposition in the absence of catalysts. The fine microstructures of the HPCs were characterized by high-resolution transmission electron microscopy. The results show that the textural features of the HPCs directly transfer from turbostratic structure in roots to a well-ordered high texture in stems. And the degree of high texture ordering decreases gradually from the stem to the tail of the HPCs. The formation mechanism of the HPCs was inferred as the comprehensive effect of polarization induction on electromagnetic fields and particle-filler property under disruptive discharge.
Key words: headstand pyrocarbon cones; chemical vapor deposition; electromagnetic-field-assisted method; fine microstructure; formation mechanism