Thermodynamics and kinetics of passive oxidation of Si3N4-bonded sic ceramics

• The oxidation reactions of Si3N4-bonded SiC ceramics are more complicated than a single component like SiC or Si3N4. The thermodynamics and kinetics of air oxidation of such ceramics in the temperature range of 900-1300 C are studied. The active to passive transition of oxidation was analysed by thermodynamic calculations using the JANAF table. The weight gain was measured using a TGA technique to study the kinetics. It is shown that all components contribute to the formation of a silica film. The kinetic results indicate that the oxidation reactions of Si3N4-bonded SiC ceramics are controlled by both an interface reaction and diffusion through the product layer. The activation energy obtained for the specimen studied is found to be comparable with that for SiC oxidation as reported in the literature

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Process Metallurgy

Processmetallurgi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)