Doctoral Dissertations

Abstract

"Calcium doped lanthanum chromite has suitable properties for use as a solid oxide fuel cell interconnect, but it is difficult to sinter. The purpose of this study was to develop methods of sintering this material in air at temperatures below 1500°C. The results are compiled into three papers.

The first paper discusses the formation of pure and Ca doped lanthanum chromate (LaCrO4). This compound transforms to lanthanum chromite (LaCrO3) and calcium chromate (CaCrO4) between 600 and 700°C which subsequently form a solid solution, (La,Ca)CrO3. The surface segregation of Ca and phase separation of CaCrO4 are discussed.

The second paper addresses the sintering behavior of (La.6Ca.4)xCrO3 where x is varied between 0.95 to 1.05. Densities of up to 93% of the theoretical were obtained by optimizing processing parameters. Compositions with x greater than or equal to unity showed the best sinterability.

The solubility of CaCrO4 in LaCrO3 versus temperature was determined and is presented in the third paper. Powders which were heated slowly had a higher apparent solvus temperature than those which started as single phase solids and were heated quickly. The optimum composition for sintering was shown to contain between 25 and 30 mol% calcium"--Abstract, page iii.

Advisor(s)

Anderson, H. U. (Harlan U.)

Committee Member(s)

Rahaman, M. N., 1950-
Huebner, Wayne
Switzer, Jay A., 1950-
Sparlin, Don M.
Nasrallah, Magdi M.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Ceramic Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 1992

Journal article titles appearing in thesis/dissertation

  • Synthesis and phase transformation of pure and calcium doped lanthanum chromate
  • The transient liquid phase sintering of calcium doped lanthanum chromite
  • Solubility of calcium in lanthanum chromite

Pagination

xvi, 112 pages

Note about bibliography

Includes bibliographical references.

Rights

© 1992 John David Carter, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 6466

Print OCLC #

28620414

Electronic OCLC #

1053901304

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