Effect of substrate on the microstructure and thermoelectric performances of Sr-doped Ca3Co4O9 thick films. Issue 5 (1st April 2019)

• Record Type: Journal Article
• Authors: Torres, M.A.; Mora, M.; Amaveda, H.; Madre, M.A.; Sotelo, A.
• Is Part Of: Ceramics international. Volume 45:Issue 5(2019)
• Page Start: 5431
• Page End: 5435
• Publication Date: 2019-04-01
• Subjects: Ceramics -- Oxides -- Thick films -- Microstructure -- Electrical properties -- Thermoelectrics; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.11.245
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Ca3 Co4 O9 thermoelectric materials in form of thick films are very promising in practical applications due to their low costs and relatively high performance. In this work, two different suspensions have been used to produce different coatings on Al2 O3 polycrystalline substrates with theoretical green thickness of 360 and 2000 µm. Moreover, the effect of substrate has also been investigated using Al2 O3 monocrystalline substrates and a 360 µm green thickness. Sintering procedure at 900 °C for 24 h has drastically decreased coating thickness. XRD performed on the coatings surface has shown the formation of small amounts of Ca3 Co2 O6 secondary phase on the polycrystalline substrates, while it was more abundant, and accompanied by Ca2 Co2 O5 on the monocrystalline substrates. In spite of the higher secondary phases content, monocrystalline substrates produced a slight grain orientation which led to the highest thermoelectric properties between the samples (0.38 mW/K 2 m at 800 °C), and very close to the best reported values in the literature.