Accession Number:

ADA191818

Title:

The Hydrothermal Dissolution of Perovskite (CaTiO3),

Descriptive Note:

Corporate Author:

ATOMIC ENERGY RESEARCH ESTABLISHMENT HARWELL (ENGLAND)

Personal Author(s):

• Myhra, S.
• Bishop, H. E.
• Riviere, J. C.

Report Date:

1986-11-01

Pagination or Media Count:

38.0

Abstract:

Perovskite CaTiO3 has been exposed to hydrothermal chemical attack in aqueous solution. Dependence on temperature 150-250 C and on duration of attack 1 to 35 days have been investigated. It was found that a precipitated surface layer was formed. The thickness of this layer ranged from a few mono-layers to several hundred nanometers for the least and the most severe hydrothermal conditions, respectively. The composition of the layer, as deduced by surface analytical techniques, suggests that i there is congruent dissolution of the perovskite surface, ii a TiO2 precipitate layer is formed, and iii the presence of silica and CO2 in solution do not appear to affect substantially the mechanism of the rate of dissolution. Keywords Nuclear waste disposal, Hydrothermal dissolution, Surface analysis.

Descriptors:

• *PEROVSKITES
• *RADIOACTIVE WASTES
• *WASTE DISPOSAL
• *CHEMICAL ATTACK(DEGRADATION)
• *DISSOLVING
• SILICON DIOXIDE
• SURFACE ANALYSIS
• WATER
• ETCHING
• ION BOMBARDMENT
• CALCIUM
• TITANIUM OXIDES
• CRYSTALLOGRAPHY
• THERMAL DEGRADATION
• AUSTRALIA

Subject Categories:

• Geology, Geochemistry and Mineralogy
• Physical Chemistry
• Radiation Pollution and Control

Distribution Statement:

APPROVED FOR PUBLIC RELEASE