Preparation and properties of continuous Al-containing silicon carbide fibers
(Key Lab of Ceramic Fibers and Composites, Institute of Aerospace and Materials Engineering, National University of Defence Technology, Changsha 410073, China)
Abstract: Continuous SiC(OAl) fibers, named KD-A fibers, were prepared by the melt-spinning of ceramic precursor polyaluminocarbosilane, air-curing, and pyrolizing at 1300℃. These fibers contained small amount of aluminum and 7%-9% oxygen. The KD-A fibers were converted into sintered SiC(Al) fibers, named KD-SA, by sintering at 1800℃. The fibers were characterized by chemical analysis, tensile strength test, SEM and XRD. The tensile strength, elastic modulus and diameter of the KD-A fibers are 2.6GPa, 210GPa, 12-14μm, respectively. The KD-A fibers have higher thermal stability, more excellent oxidation resistance than the Nicalon fibers. The properties of the KD-A fibers have reached the level of Hi-Nicalon fibers. The tensile strength, elastic modulus and diameter of the KD-A fibers are 2.1GPa, 405GPa, 10-12μm, respectively. The KD-SA fibers with nearly stoichiometric component have stable performance at high temperature, and better creep resistance than the Tyranno SA fibers.
Key words: continuous silicon carbide fibers; polyaluminocarbosilane; polymer pyrolysis