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Effect of Carbon Precursors on the Microstructure and Bonding State of a Boron–Carbon Compound Grown by LPCVD
Author(s) -
Liu Yongsheng,
Cheng Laifei,
Zhang Litong,
Yang Wenbin,
Xu Yongdong
Publication year - 2008
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2008.02207.x
Subject(s) - materials science , boron , chemical vapor deposition , x ray photoelectron spectroscopy , microstructure , carbon fibers , scanning electron microscope , coating , chemical engineering , analytical chemistry (journal) , nanotechnology , composite number , composite material , organic chemistry , chemistry , engineering
Methane (CH 4 ) and propylene (C 3 H 6 ) were used to fabricate a boron–carbon coating by a low‐pressure chemical vapor deposition (LPCVD) technique. The effects of carbon precursors on the phase, microstructure, and bonding state of the deposits have been investigated. X‐ray diffraction results show that the 2θ value of the deposit from the C 3 H 6 precursor shifts to 25.78° when the coating is deposited at 1223 K, and shifts to 26.1° when deposited at 1273 K, compared with the 2θ value of the pyrocarbon (PyC) peak deposited by LPCVD, which is 25.42°, and no boron–carbon (B–C) compound peak exists. However, the phases of coating deposited from CH 4 include B 25 C, B 13 C 2 , elemental carbon, and boron. X‐ray photoelectron spectroscopy (XPS) results show that the percent contents of boron atom in the coatings from the CH 4 precursor are 61.18% and 67.78% when deposited at 1223 and 1273 K, respectively, much higher than that from the C 3 H 6 precursor, 10.85% and 15.30%, respectively. Scanning electron microscopy (SEM) results show that the coatings deposited from CH 4 have a coarse crystal‐like morphology; however, the coatings deposited from the C 3 H 6 precursor are smooth. The formation of PyC from C 3 H 6 is more facile than that from CH 4 , which leads to differences in the phase, atom content, and microstructure of coatings from CH 4 and C 3 H 6 precursors.