Electrochemical Evaluation and Surface Characterization of Josephinite as a Natural Analog for Container Materials

Metallic Phase ◽

Localized Corrosion ◽

Natural Analog ◽

Long Term Stability ◽

Passive Behavior ◽

Cyclic Potentiodynamic Polarization ◽

High Level

AbstractA sample of josephinite, a rock containing predominantly a Ni-Fe metallic phase, was evaluated as a natural metal analog to increase confidence in the assessment of waste package performance for the potential high-level radioactive waste repository at Yucca Mountain, Nevada. The josephinite sample was characterized electrochemically in simulated groundwater environments using cyclic potentiodynamic polarization and potentiostatic tests. The passive surface layers formed potentiostatically were examined by X-ray photoelectron spectroscopy. These results were compared to those obtained with a synthetic Ni3Fe alloy with a chemical composition similar to that of josephinite. Electrochemical studies showed that josephinite exhibited passivity at a slightly higher pH than did the cast Ni3Fe alloy and was found to be slightly more susceptible to pitting corrosion. The passive films formed on the josephinite and the cast Ni3Fe alloy have a duplex structure consisting of an Fe-rich hydroxide outer layer and a Ni-rich oxide inner layer. Results obtained from this study provide an appropriate characterization of the environmental conditions leading to the passivity and localized corrosion of josephinite. Extended persistence of a stable passive film, however, is essential for the long-term stability of the josephinite sample. The relationship between the passive behavior and the formation of alteration layers needs to be established for assessing the survivability of josephinite.

Surface Characterization of Olivine-Rock by X-ray Photoelectron Spectroscopy (XPS). Leaching and U(VI) Sorption Experiments

MRS Proceedings ◽

10.1557/proc-506-321 ◽

1997 ◽

Vol 506 ◽

Cited By ~ 5

Author(s):

E. Rodrigues ◽

F.Z. El Aamrani ◽

J. Giménez ◽

I. Casas ◽

M.E. Torrero ◽

...

Keyword(s):

Secondary Phase ◽

X Ray ◽

Redox Active ◽

Leaching Experiments ◽

High Level Nuclear Waste ◽

High Level ◽

Waste Repositories

ABSTRACTHigh-FeO olivine-rock from Lovasjäarvi intrusion (SE-Finland) has been suggested as redox-active backfill-additive in deep high level nuclear waste repositories. In this w'ork, surface characterization of olivine-rock by X-Ray Photoelectron Spectroscopy (XPS) has been used in order to assess the behavior of this rock during leaching experiments and sorption properties of redox sensitive radionuclides. Uranium (VI) sorption has also been performed. Olivine leaching experiments at basic pH have shown the abundance of Fe and 0 relative to Si and Mg clearly indicating the precipitation of a Fe(III)-oxide secondary phase, probably amorphous FeOOH. At acid pH, the decrease of Mg/Si and Fe/Si ratios can be attributed to the formation of silicon dioxide on the mineral surface. The deconvolution of the 4f7 2 Uranium peak has shown the reduction of U(VI) to U(IV) onto the olivine surface.

Surface Characterization of Carbon-Bearing Magnetite (CBM) and Carbon-Bearing Ni(II)-Ferrite (CBNF)

MRS Proceedings ◽

10.1557/proc-344-169 ◽

1994 ◽

Vol 344 ◽

Author(s):

T. Sano ◽

K. Akanuma ◽

M. Tsuji ◽

Y. Tamaura

Keyword(s):

Spinel Structure ◽

Carbon Deposition ◽

X Ray Diffraction ◽

Xps Spectra ◽

X Ray ◽

Oxygen Ions ◽

Diffraction Patterns

AbstractOxygen-deficient magnetite (ODM; Fe3O4-δ, δ>0) synthesized by reduction of magnetite with H2 at 300°C decomposed CO2 to carbon with an efficiency of nearly 100% at 300°C. In this reaction, two oxygen ions of the CO2 were incorporated into the spinel structure of ODM and carbon was deposited on the surface of ODM with zero valence to form visible particles. The particles of carbon separated from ODM were studied by Raman, energy-dispersive X-ray and wave-dispersive X-ray spectroscopies. The carbon which had been deposited on the ODM was found to be a mixture of graphite and amorphous carbon in at least two levels of crystallization. X-ray photoelectron spectroscopy and X-ray diffraction patterns of the carbon-bearing magnetite (CBM) showed no indication of carbide (Fe3C) or metallic iron (α-Fe) phase formation. In the C 1s XPS spectra of the CBM, no peaks were observed which could be assigned to CO2 or CO. X-ray diffractometry, chemical analysis and TG-MS measurement showed that the carbon-bearing Ni(II)-ferrite (CBNF) (Ni(II)/Fetotal = 0.15) synthesized by the carbon deposition reaction from CO2 with the H2-reduced Ni(II)-ferrite was represented by (Ni0.28Fe2.72O4.00)1-δ (Ni2+06.9Fe2+2.31O3.00)δCτ (δ= 0.27, τ= 0.17). The carbon of the CBNF gave the CIOlayer-like oxide containing some Ni2+ ions.

Surface characterization of the high voltage LiCoO2/Li cell by X-ray photoelectron spectroscopy and 2D correlation analysis

Vibrational Spectroscopy ◽

10.1016/j.vibspec.2010.01.004 ◽

2010 ◽

Vol 53 (1) ◽

pp. 60-63 ◽

Cited By ~ 13

Author(s):

Yeonju Park ◽

Nam Hoon Kim ◽

Ja Young Kim ◽

In-Yong Eom ◽

Yeon Uk Jeong ◽

...

Keyword(s):

Correlation Analysis ◽

High Voltage ◽

X Ray ◽

2D Correlation Analysis

Surface Characterization of an Extruded 6060 Al Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.29-30.67 ◽

2007 ◽

Vol 29-30 ◽

pp. 67-70

Author(s):

Wei Zhang ◽

Jim Metson ◽

C.L. Nguyen ◽

S. Chen

Keyword(s):

Aluminium Alloy ◽

Extrusion Direction ◽

Surface Characteristics ◽

Al Alloy ◽

X Ray ◽

Film Instability ◽

Mg Content

The surface characteristics of an extruded 6060 aluminium alloy were investigated with X-ray Photoelectron Spectroscopy (XPS). The results revealed that the extruded surface was covered by oxides of aluminium and magnesium. The thickness of aluminium oxide was found to change along the extrusion direction with the thinnest and thickest oxide at the beginning and end of the extrudate, respectively. Magnesium segregation was found on the surface of the extrusion with the highest and lowest Mg concentration at the beginning and end of the extrudate, respectively. This is the inverse result of that expected where increasing Mg content was believed to be associated with film instability and thicker films.

Energetic Deposition and Surface Characterization of Thin Carbon Films on Nickel

Modern Physics Letters B ◽

10.1142/s0217984998000470 ◽

1998 ◽

Vol 12 (10) ◽

pp. 383-391

Author(s):

K. P. Adhi ◽

A. K. Sharma ◽

S. S. Wagal ◽

D. S. Joag ◽

S. K. Kulkarni

Keyword(s):

Carbon Films ◽

Polycrystalline Nickel ◽

Thin Carbon ◽

Nickel Substrates ◽

Phase Surface ◽

Electron Energy Loss ◽

Deposited Films

Thin films deposited by rapidly quenching the energetic carbon species impinging onto polycrystalline nickel substrates were studied by X-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS), and field ion microscopy (FIM). XPS and EELS of the deposited films, when compared with those recorded for graphite and synthetic diamond, indicated the growth of diamond like carbon films and amorphic diamond (a-D) phase. Surface atomic arrangement in the film is observed by FIM which magnifies the surface ~105 to 106 times. Facetting, lack of graphitic ordering, stability of the image inspite of raising or lowering the voltage about the field evaporation voltage indicate that the field ion micrograph is that of a-D.

Characterization of Surface Contaminants by a Silver Film-Enhanced IR—Johnson Method

Applied Spectroscopy ◽

10.1366/0003702971939226 ◽

1997 ◽

Vol 51 (10) ◽

pp. 1460-1463 ◽

Cited By ~ 11

Author(s):

Nobuaki Marino ◽

Kiichirou Murai ◽

Yoshinori Kataora

Keyword(s):

Polymer Film ◽

Silicon Wafer ◽

Present Method ◽

Diffuse Reflectance ◽

Silver Film ◽

Wafer Surface ◽

Surface Contaminants

Characterization of nanometer-order organic contaminants on polymer film and silicon wafer surface has been investigated by a modified IR–Johnson method. We have proposed a silver film-enhanced IR–Johnson method that is useful for surface contaminant analysis. In the present method, organic traces are transferred from the surface of a polymer film or silicon wafer onto the KBr particles deposited with silver film, and then the KBr particles are analyzed directly by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Infrared absorption of organic traces was enhanced by the presence of silver island film. With this method, a spectrum of nanometer-order organic traces can be obtained without any interference from the polymer film substrate. The present method is as surface-sensitive as X-ray photoelectron spectroscopy (XPS) and provides a large amount of information on the chemical structure of surface contaminants. This is a promising method for the surface characterization of polymer films and silicon wafer. Index Headings: Infrared; Diffuse reflectance; Surface enhancement.