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Effect of Oxygen‐Gas Concentration in the Heat‐Treatment Atmosphere and High‐Voltage Pulse Application on the Electrical Properties of Carbon Fibers
Author(s) -
Okubo Atsushi,
Miyayama Masaru,
Yanagida Hiroaki
Publication year - 1996
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1996.tb08092.x
Subject(s) - thermistor , oxygen , microstructure , carbon fibers , materials science , atmosphere (unit) , nitrogen , electrical resistivity and conductivity , oxygen gas , analytical chemistry (journal) , limiting oxygen concentration , nitrogen gas , infrared , composite material , chemistry , environmental chemistry , thermodynamics , organic chemistry , composite number , electrical engineering , engineering , physics , optics
Semiconductive carbon fibers suitable for infrared‐ray sensor materials were prepared by final heat treatments at 600°‐700°C in an atmosphere with a controlled oxygen‐gas (O 2 ) concentration, and the influence of O 2 concentration on the electrical properties and surface composition/micro ‐ structure was investigated. Resistivities at 20°C were almost equal and independent of the O 2 concentration of heat treatment in all cases, but the thermistor constant decreased as the O 2 concentration increased. Carbon fibers heat‐treated in O 2 ‐mixed nitrogen gas (N 2 ) exhibited higher surface oxygen concentrations than did those treated in pure N 2 , and surface microstructures differed between the two fibers.