The behavior of the oxide-coated Nicalon™ fibers exposed to air at 1000 °C

The behavior of Nicalon™ fibers with sol–gel derived alumina, zirconia and alumina/zirconia interfacial coatings exposed to air at 1000 °C was studied. Kinetic measurements of the oxidation rates of Nicalon™ fibers with coatings derived from different routes were conducted. Morphology, texture and composition of oxide-coated Nicalon™ fibers after exposition were studied using SEM, EDS, XRD, and XPS analysis. Some common and distinctive features of the behavior were found. In all cases the oxidation is satisfactorily described by the oxygen diffusion-controlled mechanism. Some peculiarities of behavior of oxide interfacial coatings in dependence on type oxides and their prehistory are discussed. The oxide-based interfacial coatings can be considered as promising ones but their properties must be optimized to increase the oxidation resistance of Nicalon™ fibers.