Abstract
Lanthanum chromate (LaCrO4) was synthesized as a low temperature ( < 700 °C) intermediate to perovskite-type, lanthanum chromite (LaCrO3). The lattice parameters, atom positions and bond lengths determined from X-ray powder diffraction show that LaCrO4 forms a monazite-type crystal structure. Lanthanum chromate forms a solid solution with Ca, having a solubility between 10 and 20 at%. Thermal analysis shows that at ambient oxygen pressure, LaCrO4 transforms to LaCrO3 at a temperature near 700 °C. It also indicates that (La,Ca)CrO4 initially transforms to LaCrO3 and CaCrO4 with the subsequent formation of a (La,Ca)CrO3 solid solution. Evidence of Ca segregation to the surface of (La,Ca) CrO3 particles is given by Auger electron spectroscopy and scanning electron microscopy.[/p]
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
I. Yasuda andT. Hikita, in Proceedings of the Second International Symposium on Solid Oxide Fuel Cells, Athens, Greece, 1991, edited by F. Gross, P. Zegers, S. C. Singhal, and O. Yamamoto. (Commission of the European Communities, Luxembourg, 1991) p. 645.
N. Sakai, T. Kawada, H. Yokokawa, M. Dokiya andT. Iwata,Solid State Tonics 40/41 (1990) 394.
N. Sakai, T. Kawada, H. Yokokawa, M. Dokiya andI. Kojima,T. Amer. Ceram. Soc. 76 (1993) 609.
J. D. Carter, Ph.D. Dissertation, University of Missouri-Rolla, Rolla MO, (1992).
L. A. Chick, T. R. Armstrong, D. E. McCready, G. W. Coffey, G. D. Maupin andJ. L. Bates, in Proceedings of the Third International Symposium on Solid Oxide Fuel Cells, Honolulu, 1993, Vol. 93–4, edited by S.C. Singhal, and H. Iwahara, (Pennington, NJ, The Electrochemical Society, Inc., 1993) p. 374.
J. D. Carter, V. Sprenkle, M. M. Nasrallah, andH. U. Ander Son,in Proceedings of the Third International Symposium on Solid Oxide Fuel Cells; Honolulu, 1993, Vol. 93-4, edited by S. C. Singhal, and H. Iwahara, (Pennington, NJ, The Electrochemical Society, Inc., 1993) p. 344.
L. Tai andP. Lessing,J. Mater. Res. 7 (1992) 511.
JCPDS Card # 36-93, (Joint Committee on Powder Diffraction Standards, Swarthmore, PA, 1986); andS. G. Manca andE. J. Baran,15 (1982) 102.
J. W. Visser,Ibid 2 (1969) 89.
MathCAD Ver. 2.5, Mathsoft, Inc. (1989).
A. Sakthivel andR. A. Young, in the users guide to DBWS-9006 and DBWS-9006PC programs for Rietveld analysis of X-ray and neutron powder diffraction patterns, (Georgia Institute of Technology, Atlanta, GA, 1992).
“Structure Reports” Vol. 17, edited by A. J. C. Wilson, (Oosthoek, Utrecht, Netherlands, 1963) p. 487.
H. U. Anderson, C. C. Chen, J. C. Wang andM. J. Pennell, in “Ceramic transactions Vol. 12, Ceramic powder science III”, edited by G. L. Messing, S. Hirano, and H. Hausner (American Ceramic Society, Westerville, OH, 1990) p. 749.
C. Giacovazzo, in “Fundamentals of crystallography”, edited by C. Giacovazzo (Oxford University Press, New York; 1992) p. 109.
JCPDS Card #8-458, (Joint Committee on Powder Diffraction Standards, Swarthmore, PA, 1958); and US National Bureau, of Standards Circular 539, 7, (1957) p. 13.
R. W. G. Wyckoff, “Crystal structures”, 2nd edn, Vol. 3 (J Wiley and Sons, New York, 1965) p. 15.
C. Khattak andD. Cox,Mater. Res. Bull. 12 (1977) 463.
W. F. Ford andJ. White,Trans. Br. Ceram. Soc. 48 (1949) 417.
Z. Pánek,Silikáty 25 (1981) 169.
A. Kaiser, B. Sommer andE. Woermann,J. Amer. Ceram. Soc. 75 (1992) 1463.
E. D. Hondros andM. P. Seah,Int. Metall. Rev. 22 (1977) 262.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Carter, J.D., Anderson, H.U. & Shumsky, M.G. Structure and phase transformation of lanthanum chromate. J Mater Sci 31, 551–557 (1996). https://doi.org/10.1007/BF01139176
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01139176