Pore depth evolution of a pyrochlore pellet

DOI

The long-term stability of ceramic materials that are considered as potential nuclear waste forms is governed by heterogeneous surface reactivity. Thus, instead of a mean rate, the identification of one or more dominant contributors to the overall dissolution rate is the key to predict the stability of waste forms quantitatively. Direct surface measurements by vertical scanning interferometry (VSI) and their analysis via material flux maps and resulting dissolution rate spectra provide data about dominant rate contributors and their variability over time. Using pyrochlore (Nd2Zr2O7) pellet dissolution under acidic conditions as an example, we demonstrate the identification and quantification of dissolution rate contributors, based on VSI data and rate spectrum analysis. Heterogeneous surface alteration of pyrochlore varies by a factor of about 5 and additional material loss by chemo-mechanical grain pull-out within the uppermost grain layer. We identified four different rate contributors that are responsible for the observed dissolution rate range of single grains. Our new concept offers the opportunity to increase our mechanistic understanding and to predict quantitatively the alteration of ceramic waste forms.

Supplement to: Fischer, Cornelius; Finkeldei, Sarah; Brandt, Felix; Bosbach, Dirk; Lüttge, Andreas (2015): Direct Measurement of Surface Dissolution Rates in Potential Nuclear Waste Forms: The Example of Pyrochlore. ACS Applied Materials & Interfaces, 7(32), 17857-17865

Identifier
DOI https://doi.org/10.1594/PANGAEA.855413
Related Identifier https://doi.org/10.1021/acsami.5b04281
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.855413
Provenance
Creator Fischer, Cornelius ORCID logo; Finkeldei, Sarah; Brandt, Felix ORCID logo; Bosbach, Dirk; Lüttge, Andreas ORCID logo
Publisher PANGAEA
Publication Year 2015
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 24 data points
Discipline Earth System Research