Community Research and Development Information Service - CORDIS


To improve process efficiency at increasingly higher temperatures and in aggressive environments, metallic alloys need either to be coated or replaced by other high temperature materials such as structural ceramics. Under high PO(2) atmospheres, for example air, water vapour or carbon dioxide, oxidation usually follows parabolic kinetics due to the formation of a protective silicon dioxide-rich layer which results in a net weight gain (passive oxidation). Under low PO(2) atmospheres, for example H(2), material losses are recorded due to the formation of gaseous species such as SiO and N(2) (active oxidation). This paper contrasts the differences between passive and active oxidation and highlights the mechanisms responsible for the degradation of a commercially available silicon nitride densified with Y(2)O(3) and Al(2)O(3) in the temperature range 1200 to 1300 C in air and hydrogen with small additions of water vapour.

Additional information

Authors: OLIVEIRA F A C, MIE/INETI-DTM, Lisboa (PT);FORDHAM R J, JRC Petten (NL);DE WIT J H W, TU Delft (NL)
Bibliographic Reference: Paper presented: Third European Ceramics Society Conference, Madrid (ES), September 12-17, 1993
Availability: Available from (1) as Paper EN 37761 ORA
Record Number: 199311322 / Last updated on: 1994-11-28
Original language: en
Available languages: en