High Temperature Corrosion of a Porous Si2N2O-ZrO2 Composite Material

• Published in: Key engineering materials 1997, Vol.132-136, p.1572-1575
• Main Authors: O'Meara, Colette, Chen, Jiaxin, Pompe, Robert, Heim, Maiken, Gatt, Refael
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; Structural ceramics; Technical ceramics
• ISSN: 1013-9826; 1662-9795; 1662-9795
• DOI: 10.4028/www.scientific.net/KEM.132-136.1572

The hot corrosion behavior of a low-cost porous Si2N2O-ZrO2 composite material, fabricated without the use of sintering additives, was studied in pure oxygen, humid oxygen, and salt aerosol environment. For salt corrosion, a special test rig was used to simulate salt deposition in real combustion environments. Samples were exposed at different temperatures between 800 and 1520 C. It was found that during oxidation up to 1100 C only Si2N2O is involved in the reaction, silica is formed and the weight gain obeys a parabolic rate law. At greater than 1100 C divergence from the pure parabolic regime increases with increasing temperature. At these temperatures SiO2 and ZrO2 start to form a protective zirconium silicate layer which inhibits the parabolic oxidation of Si2N2O. The formation of amorphous silica on Si2N2O was found to be faster than on Si. Pre-oxidation treatment at high temperatures significantly improves the oxidation resistance at lower temperatures. Water vapor was found to be a more aggressive oxidizing species than O2 and can significantly enhance oxidation. Wet oxidation with or without salt has been found to enhance oxidation and corrosion at temperatures of -1250 C. This effect is less profound at higher temperatures. The lowest weight gains were observed at temperatures greater than 1300 C. (Author)