Fabrication and characterization of NiO bicrystals

Book · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:94046

Chung, Y C; Wuensch, B J ^[1]

---

1. Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

Fabrication of NiO bicrystals have {Sigma}5 (310) and {Sigma}13 (510) coincidence-site tilt boundaries was successfully carried out by a CVT (Chemical Vapor Transport) method. The CVT method was a very advantageous way to grow ultra pure crystals since it preferentially transported NiO from the source pellet to the substrate by reaction with a HCl carrying gas. Single crystal MgO was used as a substrate for epitaxial growth of NiO as the readily available MgO crystals have only a 1% lattice mismatch with NiO. Moreover, MgO is soluble in acids while NiO is not. This permitted removal of the substrate crystal after growth to provide a free-standing NiO crystal. Using Two single crystals of MgO with the desired tilt orientation as a substrate, NiO bicrystals were fabricated at growth rates greater than 100 {mu}m/hour at 1400K using 250 torr of HCl(g) as a carrying agent. The purity of the epitaxial NiO crystals was determined by mass spectrometry and neutron activation analysis. The grain boundary in the bicrystals is exactly perpendicular to the (100) growth surface. Highly-reflective facets along the growth direction suggest high mechanical quality. High-resolution transmission electron microscopy of the {Sigma}13 boundary revealed structure at the atomic scale that provided no evidence for segregated phases.

• OSTI ID: 94046
• Report Number(s): CONF-941144--; ISBN 1-55899-258-8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BICRYSTALS
CRYSTAL STRUCTURE
EXPERIMENTAL DATA
GRAIN BOUNDARIES
HYDROCHLORIC ACID
MAGNESIUM OXIDES
MASS SPECTROSCOPY
NEUTRON ACTIVATION ANALYSIS
NICKEL OXIDES
OPTICAL MICROSCOPY
PLATINUM
SAMPLE PREPARATION
SCANNING ELECTRON MICROSCOPY
TRANSMISSION ELECTRON MICROSCOPY
VAPOR PHASE EPITAXY