|
|
|
| The Influence of Deposition Parameters on the Microstructure and Deposition Mechanism of Low-temperature Isotropic Pyrocarbon on a Bed of Fluidized Particles |
| ZHANG Jian-hui, RUAN Ye-peng, LUO Bi-hui, ZHENG Yan-zhen |
| School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China |
|
|
|
|
Abstract To investigate the microstructure and deposition mechanism of low-temperature isotropic pyrocarbon (LTIC), chemical vapour deposition was conducted in a steady-state fluidized bed using different propane concentrations and deposition temperatures. The microstructure of LTIC obtained at different deposition conditions was characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that LTIC is composed of both globular-like and laminar structures. Increasing the deposition temperature is propitious for decreasing the nucleation barrier-forming pyrocarbon in vapour, causing the quantity of spherical particles with a smaller diameter to increase and the texture of the outer layer around carbon blacks inside the spherical particles to decrease gradually. Increasing the propane concentration also made the globular-like fracture morphology more obvious and caused the laminar structure to gradually disappear. Pyrocarbon formation is dominated by a surficial growth mechanism at lower propane concentrations, while gaseous nucleation mechanism is more dominant at higher propane concentrations.
|
|
Received: 05 October 2019
|
|
|
| Fund:National Natural Science Foundation of China; grant number: 50975070; grant sponsor: Zhejiang Provincial Science Foundation of China; grant number: LY12E05002 |
|
Corresponding Authors:
ZHANG Jian-hui. E-mail: zhangjh@hdu.edu.cn
|
|
|
|
[1] Agnès O.Pyrocarbons[J]. Carbon, 2002, 40(1): 7-24.
[2] Chambers J.Prosthetic heart valves[J]. The International Journal of Clinical Practice, 2014, 68(10): 1227-1230.
[3] Li X, Wu JF, Shuo B.Fabrication and microstructure of boron-doped isotropic pyrolytic carbon[J]. Carbon, 2012, 50(12): 4705-4710.
[4] Zhang MY, Su ZA, Xie ZY, et al.Microstructure of pyrocarbon with chemical vapor infiltration[J]. Procedia Engineering, 2012, 27: 847-854.
[5] López-Honorato E, Meadows PJ, Xiao P, et al.Structure and mechanical properties of pyrolytic carbon produced by fluidized bed chemical vapor deposition[J]. Nuclear Engineering and Design, 2008, 238(11): 3121-3128.
[6] Ahmad KA, Ahmad FA, Balendu CV, et al.Prosthetic heart valves: Types and echocardiographic evaluation[J]. International Journal of Cardiology, 2007, 122(2): 99-110.
[7] López-Honorato E, Meadows PJ, Xiao P.Fluidized bed chemical vapor deposition of pyrolytic carbon - I. Effect of deposition conditions on microstructure[J]. Carbon, 2009, 47(2): 396-410.
[8] Zhang DS, Li KZ, Li HJ, et al.The influence of deposition temperature on the microstructure of isotropic pyrocarbon obtained by hot-wall chemical vapor deposition[J]. Journal of Materials Science, 2011, 46(10): 3632-3638.
[9] Lacroix R, Fournet R, Ziegler-Devin I, et al.Kinetic modeling of surface reations involved in CVI of pyrocarbon obtained by propane pyrolysis[J]. Carbon, 2010, 119(1): 132-144.
[10] Ziegler-Devin I, Fournet R, Lacroix R, et al.Pyrolysis of propane for CVI of pyrocarbon. Part IV: Main pathways involved in pyrocarbon deposit[J]. Journal of Analytical and Applied Pyrolysis, 2013, 104: 48-58.
[11] Zhang JH, Sun HB, Wang GM, et al.Microstructure of silicon-alloyed pyrocarbon for mechanical heart valves[J]. Chinese Journal of Biomedical Engineering, 2011, 30(5): 757-761.
[12] Delhaes P.Chemical vapor deposition and infiltration processes of carbon materials[J]. Carbon, 2002, 40(5): 641-657.
[13] Zhang JH, Sun HB, Wang GM, et al.Degree of preferred orientation of pyrocarbon for artificial mechanical heart valve by selected area electron diffraction[J]. Journal of Central South University (Science and Technology), 2013, 44(3): 1006-1010.
[14] Zhou R, Lee R, Claye A, et al.Layer disorder in carbon anodes[J]. Carbon, 1998, 36(12): 1777-1781.
[15] Je JH, Lee JY.The cause of size difference: Soot particles and the growth features of isotropic pyrolytic carbon[J]. Carbon, 1987, 25(4): 586.
[16] Kaae JL.The mechanism of the deposition of pyrolytic carbon[J]. Carbon, 1985, 23(6): 665-673.
[17] Jung HJ, Lee JY.How is pyrolytic carbon formed? Transmission eletron micrographs which can explain the change of its density with deposition temperature[J]. Carbon, 1984, 22(3): 317-319.
[18] Feron O, Langlais F, Naslain R.Analysis of the gas phase by in situ FTIR spectrometry and mass spectrometry during the CVD of pyrocarbon from propane[J]. Chemical Vapor Deposition, 1999, 5(1): 37-47.
[19] Lavenac J, Langlais F, Feron O, et al.Microstructure of the pyrocarbon matrix in carbon/carbon composites[J]. Composites and Technology, 2001, 61: 339-345.
[20] Dong GL, Huttinger KJ.Consideration of reaction mechanisms leading to pyrolytic carbon of different texture[J]. Carbon, 2002, 40(14): 2515-2528.
[21] Bourrat X, Lavenac J, Langlais F, et al.The role of pentagons in the growth of laminar pyrocarbon[J]. Carbon, 2001, 39(15): 2376-2380.
[22] Hu ZJ, Zhang WG, Hüttinger KJ, et al.Influence of pressure, temperature and surface area/volume ratio on the texture of pyrolytic carbon deposited from methane[J]. Carbon, 2003, 41(4): 749-758.
[23] Erdemir D, Lee AY, Myerson AS.Nucleation of crystals from solution: Classical and two-step models[J]. Accounts of Chemical Research, 2009,42(5): 621. |
| [1] |
Li Baoming, Hu Jiarui, Xu Haijun, Wang Cong, Jiang Yanni, Zhang Zhihong, Xu Jun. Deep Cascaded Network for Automated Detection of Cancer MetastasisRegion from Whole Slide Image of Breast Lymph Node[J]. Chinese Journal of Biomedical Engineering, 2020, 39(3): 257-264. |
| [2] |
Xu Jie, Wang Xunheng, Li Lihua. Investigating Brain Networks for ADHD Children Based on Phase Synchronization of Resting State fMRI[J]. Chinese Journal of Biomedical Engineering, 2020, 39(3): 265-270. |
|
|
|
|
