Faserverstärkte oxidkeramische Werkstoffe

Abstract

Oxide ceramics display excellent thermal and chemical stability up to high temperatures. A suitable way to overcome the inherent brittleness of oxide ceramics is the reinforcement with oxide fibers. Although both constituents, fibers and matrices are brittle, the composites display quasi-ductile deformation behavior, due to mechanisms such as crack deflection, crack bridging or fiber pull-out. A premise for these mechanisms to work is the relatively weak bonding between fibers and the matrix. To achieve a weak fiber/matrix bonding either suitable fiber coatings are employed or, in an alternative approach, highly porous matrices are used. WHIPOX, developed at DLR is a ceramic matrix composite belonging to the porous matrix group. These materials have a high potential for thermal protection systems and liners in gas turbine engines and beyond.

Injection Moulding of Oxide Ceramic Matrix Composites: Comparing Two Feedstocks

“…Higher temperatures should be avoided, as the mechanical properties of the Nextel 610 fibre will be degraded above a temperature of 1200 °C. This is due to the coarsening of the ceramic grains of the fibres [7]. Some of the samples produced with the WMC-matrix could not keep their shape stability.…”