Parabolic-Non-Parabolic Oxidation Kinetics of Si3N4
1993 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, Vol. 12, no 3, 177-184 p.Article in journal (Refereed) Published
The isothermal oxidation behaviour of Si3N4, HIP sintered without additives, has been investigated thermogravimetrically in the temperature range 1250–1500°C. The formed oxide scales were found to be partly crystalline, and the obtained weight gain curves followed the parabolic rate law after a certain time, t0, but not during the entire oxidation experiment. In the time interval t<t0 the curves have been interpreted with the rate law , which is developed with the assumption that the cross-section area available for oxygen diffusion decreases during the experiment, due to a crystallization process and to formation of nitrogen bubbles within the oxide scale. The rate constants, Kp were calculated from the constants in the arctan function, and the activation energy could be determined to be 310±25 kJ/mol. The oxygen diffusion rates found are in fair agreement with those obtained for amorphous silica.
Place, publisher, year, edition, pages
1993. Vol. 12, no 3, 177-184 p.
IdentifiersURN: urn:nbn:se:liu:diva-60871DOI: 10.1016/0955-2219(93)90119-COAI: oai:DiVA.org:liu-60871DiVA: diva2:359607