Abstract
Surface oxidation of the hot-pressed and reaction-sintered silicon carbide ceramics specimens after 0.86 year, 2.4 year and 3.8 year space exposure was evaluated using mainly secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The oxygen content of both space-exposed silicon carbide specimen's surface where was not covered by a fixture jig increased markedly compared with those of blank, AO-irradiated specimens' surface and the covered part of the space-exposed specimens' surface. Oxidized layer thickness of the space-exposed specimens after 0.86 year, 2.4 year and 3.8 year exposure was about 10 nm, 50 nm and 90 nm, respectively. The surface oxidized layer was consisted of mostly pure SiO2 and a thin intermediate layer or a mixed layer was existed. Surface roughness of both the space-exposed specimens after 3.8 year and the AO-irradiated specimens after irradiation of corresponding three years on the orbital increased compared with the blank specimens, 2.4 year space-exposed and one year AO-irradiated specimens. The oxidation may caused mainly by the collision of atomic oxygen but other effects should be considered.
