Interfacial segregation in perovskites. Part 2; Experimental evidence

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1990.tb06467.x· OSTI ID:5162112

Desu, S B ^[1]; Payne, D A ^[2]

---

1. Dept. of Materials Engineering, Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (US)
2. Dept. of Materials Science and Engineering, and Materials Research Lab., Univ. of Illinois at Urbana-Champaign, Urbana, IL (US)

This paper reports on experimental evidence determined by scanning transmission electron microscopy, scanning Auger electron spectroscopy, and lattice parameter measurements for interfacial segregation in pure and doped perovskite materials, e.g., BaTiO{sub 3} and SrTiO{sub 3}. The segregation behavior for isovalent dopants (e.g., Sr{sup 2+}, Ca{sup 2+}, or Pb{sup 2+} at a Ba{sup 2+} site) is mainly associated with a strain energy contribution from ionic misfit. However, both strain energy and space charge contributions are important in determining the segregation behavior of aliovalent ions (e.g., La{sup 3+}, or Nd{sup 3+} at a Ba{sup 2+} site and Fe{sup 3+} or Ni{sup 3+} at a Ti{sup 4+} site). Segregation depths for aliovlent dopants are typically 15 to 20 nm thick. Besides dopants, constituent alkaline-earth ions also segregate to interfaces. Their segregation behavior is promoted by high temperatures, low partial pressures of oxygen, and the presence of acceptors. The results are explained in terms of a proposed theory of segregation.

• DOE Contract Number: AC02-76ER01198
• OSTI ID: 5162112
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Journal Issue: 11 Vol. 73:11; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
AUGER ELECTRON SPECTROSCOPY
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
DOPED MATERIALS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
HIGH TEMPERATURE
IONS
IRON IONS
LANTHANUM IONS
MATERIALS
MICROSCOPY
NEODYMIUM IONS
NICKEL IONS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PEROVSKITES
SEGREGATION
SPECTROSCOPY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY