Enhancing thermal stability of oxide ceramic matrix composites via matrix doping. Issue 7 (July 2022)

• Record Type: Journal Article
• Authors: Almeida, Renato S.M.; Farhandi, Hedieh; Tushtev, Kamen; Rezwan, Kurosch
• Is Part Of: Journal of the European Ceramic Society. Volume 42:Issue 7(2022)
• Page Start: 3282
• Page End: 3289
• Publication Date: 2022-07
• Subjects: Ceramic matrix composites -- Nextel 610 -- Alumina -- Magnesia -- Grain growth; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2022.02.040
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: To overcome the main limitation of oxide ceramic matrix composites (Ox-CMCs) regarding thermal degradation, the use of matrix doping is analyzed. Minicomposites containing Nextel 610 fibers and alumina matrices with and without MgO doping were produced. The thermal stability of the minicomposites was evaluated considering their microstructure and mechanical behavior before and after thermal exposures to 1300 °C and 1400 °C for 2 h. Before heat treatment, both composite types showed very similar microstructure and tensile strength. After heat treatment, densification, grain growth and strength loss are observed. Furthermore, the MgO dopant from the matrix diffuses into the fibers. As a result, abnormal fiber grain growth is partially suppressed and MgO-doped composites show smaller fiber grains than non-doped composites. This more refined microstructure leads to higher strength retention after the heat treatments. In summary, doping the matrix can increase the overall thermal stability without impairing the room-temperature properties of Ox-CMCs.