Drastic enhancement of mechanical properties of Ca3Co4O9 by B4C addition. Issue 1 (January 2021)

• Record Type: Journal Article
• Authors: Amaveda, Hippolyte; Mora, Mario; Dura, Oscar J.; Torres, Miguel A.; Madre, Maria A.; Marinel, Sylvain; Sotelo, Andres
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 1(2021)
• Page Start: 402
• Page End: 408
• Publication Date: 2021-01
• Subjects: Ceramics -- Oxides -- Mechanical properties -- Thermoelectric properties -- Thermal expansion; 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.2020.08.024
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Ca3 Co4 O9 with B4 C additions in different proportions (0, 0.10, 0.25, 0.5, and 0.75 wt.%) have been fabricated using the classical solid-state method. Powder XRD patterns have displayed that Ca3 Co4 O9 phase is the major one in all samples. Microstructural observations showed that B4 C has been superficially oxidized, producing liquid B2 O3 during sintering, and reacting with the Ca3 Co4 O9 grains to produce bridges between them. In spite of the increase of porosity, these bridges led to an important raise (more than two times) of mechanical properties when compared to the pristine materials. On the other hand, while B4 C addition has not influenced S values, it has decreased electrical resistivity, thermal conductivity, and thermal expansion. Consequently, ZT values have been also increased, reaching 0.24 at 800 °C in 0.25 wt.% B4 C containing samples, which is very close to the best values reported in the literature, and two times higher than the obtained in pure materials in this work.