Oxidation behavior of ZrB_2-SiC-ZrO_2 ceramic composites in the temperature range of 800-1200℃

摘要

ZrB_2-10 vol.% SiC ceramics were hot pressed with addition of two contents of ZrO_2, i.e., 10 vol.% and 20vol.%. Oxidation behavior of ZrB_2-SiC-ZrO_2 ceramics was investigated using muffle furnace in the temperature range of 800-1200 ℃ in air. With the increase in temperature and extension in holding time, two ceramics both presented more and more severe oxidation behavior. Comparatively, results of microstructure indicated that ceramic with 10 vol.% ZrO_2 always exhibited lighter variation in structure after oxidation. Further discussion showed that ceramic with 10 vol.% ZrO_2 also provided lower mass gain and thinner oxidized layer. Analysis of oxidation mechanism revealed that excessive addition of ZrO_2 brought much path to the inward transport of oxygen and therefore led to the serious oxidation for ZrO_2-SiC-ZrO_2 ceramics.