Phase equilibria and crystal chemistry of the CaO–½Sm2O3–CoOz system at 885 °C in air
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
- Univ. of Maryland, College Park, MD (United States). Dept. of Chemistry and Biochemistry
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Illinois Inst. of Technology, Chicago, IL (United States)
The CaO–½Sm2O3–CoOz system prepared at 885 °C in air consists of two calcium cobaltate compounds, namely, the 2D thermoelectric oxide solid solution, (Ca3$$-$$xSmx)Co4O9$$-$$z (0 ≤ x ≤ 0.5) which has a misfit layered structure, and the 1D Ca3Co2O6 which consists of chains of alternating CoO6 trigonal prisms and CoO6 octahedra. Ca3Co2O6 was found to be a point compound without the substitution of Sm on the Ca site. A solid solution region of distorted perovskite, (Sm1$$-$$xCax)CoO3$$-$$z (0 ≤ x ≤ 0.22, space group Pnma) was established. The reported Sm2CoO4 phase was not observed at 885 °C, but a ternary Ca-doped oxide, (Sm1+xCa1$$-$$x)CoO4$$-$$z (Bmab) where 0 < x ≤ 0.15 was found to be stable at this temperature. In the peripheral binary systems, Sm was not present in the Ca site of CaO, while a small solid solution region was identified for (Sm1$$-$$xCax)O(3$$-$$z)/2 (0 ≤ x ≤ 0.075). Lastly, ten solid solution tie-line regions and six three-phase regions were determined in the CaO–½Sm2O3–CoOz system in air.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1245143
- Alternate ID(s):
- OSTI ID: 1251268
- Journal Information:
- Solid State Sciences, Vol. 48, Issue C; ISSN 1293-2558
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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