In situ formation of oxidation resistant refractory coatings on SiC-reinforced ZrB 2 ultra high temperature ceramics

Abstract

In situ oxidation resistant and solid refractory coatings have been generated on 20 vol% SiC-reinforced ZrB 2 ultra high temperature ceramics containing 10 wt% rare earth (RE) additives such as LaB 6, La 2O 3, and Gd 2O 3 fabricated by spark plasma sintering. Oxidation for 1 h at 1600°C in static air led to formation of a dense layer (up to 250 μm thick) of ZrO 2 and RE-zirconates on the composite systems underneath which were intermediate layers (50-100 μm) containing heterogeneous crystalline oxides such as La 2Zr 2O 7 and amorphous silicate phases. The benefits of predominating solid oxidation products over having substantial volumes of liquid present in aerospace leading edge applications are discussed. © Published 2012 by Wiley Periodicals, Inc.