Thermal properties of homogenous lanthanum hexaaluminate/alumina composite ceramics

• Published in: Journal of the European Ceramic Society 2010-11, Vol.30 (15), p.3103-3109
• Main Authors: Negahdari, Zahra, Willert-Porada, Monika, Scherm, Florian
• Format: Article
• Language: English
• Subjects: Aluminum oxide; B. Composites; C. Thermal conductivity; C. Thermal properties; Ceramics; D. Al 2O 3; Heat transfer; Lanthanum; Lanthanum hexaaluminate (LaAl 11O 18); Mechanical properties; Sinterability; Thermal barrier coatings; Thermal conductivity; Thermal properties
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2010.07.026

Lanthanum hexaaluminate has the potential to be applied in thermal barrier coatings due to its relative low thermal conductivity and low sinterability at temperatures higher than 1100 °C. One of the main problems in developing this material as a thermal barrier coating is difficulty in controlling the microstructure in order to combine the low thermal conductivity with high structural reliability. The idea behind this study was to take advantage simultaneously of the low thermal conductivity of lanthanum hexaaluminate and of the high mechanical properties of alumina by developing alumina-rich and lanthanum hexaaluminate-rich alumina/lanthanum hexaaluminate ceramic composites. The thermal properties of the alumina/hexaaluminate ceramic composites were compared as a function of temperature and lanthanum hexaaluminate content (20–80 vol.%). The results showed that the alumina/lanthanum hexaaluminate ceramic composites have sufficient low thermal conductivity to be used in thermal barrier coatings.