Active‐to‐Passive Transition and Bubble Formation for High‐Temperature Oxidation of Chemically Vapor‐Deposited Silicon Carbide in CO–CO₂ Atmosphere

Abstract

Oxidation behavior of chemically vapor-deposited Sic in11. Experimental Procedure CO-CO, atmospheres (0.1 MPa j was investigated using a thermogravimetric technique at temperatures from 1823 to 1923 K. Active or passive oxidation was observed CVD-SIC (p type) plates were prepared on graphite substrates using SiCI,, C,H,, and H, as source gases. Specimens for oxidation tests were o.5 mm in thickness and mm in diamedepending On temperature and coZ/co partial pressure ratio ('C02/'CO)*The for the tranter. All specimens were polished with diamond paste to 1 ,,m and then ultrasonically cleaned in acetone and ethyl alcohol. pCOi/pCOMass changes in the specimens were continuously measured by thermogravimetry at temperatures from 1823 to 1923 K. The specimens were suspended from an electrobalance (Model R-100, Cahn Instruments, Cerritos, CA) in an alumina reaction sition was 10' times as large as a theoretical value calculated from the Wagner mode'. In the passive Oxidation above 1873 K, SiO, bubbles were grown-The expansion and ruPture of bubbles caused cyclic rapid mass gain and mass loss.

Handbook of SiC properties for fuel performance modeling

“…The SiC powder can be oxidized in air at 973 K [174]. Moreover, the formation of SiO 2 bubbles at extremely high temperatures can be closely related to the oxidation mechanism of SiC [164,172]. The transition from passive oxidation to bubble formation depends on the oxygen partial pressure and test temperature.…”

“…Many studies on the oxidation behavior of SiC have been conducted [159][160][161][162][163][164][165][166][167][168][169][170][171][172][173][174] (see also Refs. [175,176] for recent reviews of the oxidation of SiC).…”

Photoemission of the SiO2–SiC heterointerface

“…[1][2][3][4][5][6] SiC has long been considered as an ideal material for high power devices, and is favored over other wide-band-gap materials. Silicon carbide devices promise outstanding performance parameters due to the physical and electronic properties of the material, such as wide band gap, high thermal conductivity, and high electron mobility.…”

Corrosion of Ceramic Materials

“…results in the formation of large bubbles in the oxide layer on the surfaces of the SiC components and a transition from passive to active oxidation (active II) (Jacobson, 1993;Narushima et al, 1994b) ( Figure 5). The same mechanism is also known for Si 3 N 4 ceramics Above the oxide scale decomposition temperature, simple decomposition and evaporation reactions of SiC into Si and carbon and of Si 3 N 4 materials into Si and N can also take place.…”