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Structural Evolution in Sol–Gel‐Derived Yttrium Aluminum Garnet–Alumina Precursor Fibers
Author(s) -
Krüger Reinhard,
Glaubitt Walther,
Löbmann Peer
Publication year - 2002
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.1151-2916.2002.tb00535.x
Subject(s) - pyrolysis , materials science , amorphous solid , fiber , composite material , gas pycnometer , chemical engineering , nitrogen , eutectic system , adsorption , water vapor , sintering , porosity , microstructure , chemistry , organic chemistry , engineering
A sol leading to a eutectic Al 2 O 3 –Y 3 Al 5 O 12 composition was spun into fibers. These fibers were dried and pyrolyzed between 200° and 850°C in a nitrogen or water‐vapor atmosphere. Pyrolysis in nitrogen resulted in dense, amorphous fibers with considerable residual carbon content. In water vapor, fibers also remained amorphous, but organics were almost completely removed. The loss of organics created micropores that grew as the pyrolysis temperature increased. The amorphous fiber structures were examined by nitrogen adsorption, helium pycnometry, and transmission electron microscopy. Young's moduli of the pyrolyzed fibers were measured, and porosities of the fibers were calculated from both nitrogen‐adsorption data and elastic behavior. Sintering tests showed the best sinterability for fibers pyrolyzed in water vapor to 385°–500°C.