ZrB2 and ZrB2-SiC composites containing 40 and 60 mass% SiC were prepared by spark plasma sintering (SPS) at temperatures of 1810 and 1770°C for 300 s under a pressure of 40 MPa. Oxidation behavior of these samples was characterized by exposing them to 1400, 1500, and 1600°C in an ambient atmosphere for 180 min, and by measuring the weight gains of the sample. The oxide layers were characterized by field emission scanning electron microscopy with energy dispersive spectroscopy analysis. At 1400 and 1500°C, layered structures consisted of a SiO2 rich outer layer, a thin ZrO2-SiO2 layer, ZrO2-containing layer and unaffected ZrB2-SiC. However, at 1600°C, active oxidation of SiC was observed and changed oxidation mechanism significantly. The consumption of SiC particles resulted in a formation of oxide regions mainly composed of SiO or SiO2 and ZrO2. Unaffected ZrB2-SiC region was not observed at 1600°C.
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