Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy

Matt, Sarah M.; Haschke, John M.; McLean, William; Dinh, Long N.

doi:10.1021/acs.jpca.9b09951

Title: Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy

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Abstract

Lithium hydride (LiH) is a unique, ionic compound with applications in a variety of industries. Unfortunately, LiH is very reactive toward H₂O even at ppm levels, forming oxide (Li₂O) and hydroxide (LiOH) corrosion layers while outgassing H₂. An effective means to eliminate unwanted outgassing is vacuum-heating to convert LiOH into Li₂O, although subsequent re-exposure to moisture during transport/handling reconverts some Li₂O back to LiOH. A corrosion growth model for previously vacuum-baked LiH is necessary for long-term prediction of the hydrolysis of LiH. In this work, a para-linear hydroxide corrosion growth model is proposed for the reaction of previously vacuum-baked LiH samples with moisture. This model, composed of two competing diffusion reaction fronts at the LiOH/Li₂O and Li₂O/LiH interfaces, is validated experimentally by subjecting a previously vacuum-baked polycrystalline LiH sample to 35 ppm of H₂O at room temperature while monitoring the corrosion growth as a function of time with diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. The para-linear growth model for the hydrolysis of previously vacuum-baked LiH proposed in this report can also serve as a template for the hydrolysis of other hygroscopic oxides grown on metal or metal hydride substrates.

Authors:

Matt, Sarah M. ^[1]; Haschke, John M. ^[1]; McLean, William ^[1];

^[1]

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: 2019-12-20

Research Org.:: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:: 1597620

Report Number(s):: LLNL-JRNL-778562
Journal ID: ISSN 1089-5639; 971570

Grant/Contract Number:: AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Additional Journal Information:: Journal Volume: 124; Journal Issue: 2; Journal ID: ISSN 1089-5639

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Electrochemistry; Moisture; Interfaces; Diffusion; Oxidation

Citation Formats


                    Matt, Sarah M., Haschke, John M., McLean, William, and Dinh, Long N. Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy.  United States: N. p., 2019. 
Web.  doi:10.1021/acs.jpca.9b09951.

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                    Matt, Sarah M., Haschke, John M., McLean, William, & Dinh, Long N. Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy.  United States.  https://doi.org/10.1021/acs.jpca.9b09951

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                    Matt, Sarah M., Haschke, John M., McLean, William, and Dinh, Long N. Fri .  
"Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy".  United States.  https://doi.org/10.1021/acs.jpca.9b09951.  https://www.osti.gov/servlets/purl/1597620.

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@article{osti_1597620,

  title        = {Moisture Corrosion of LiH: A Kinetic Investigation by DRIFT Spectroscopy},

  author       = {Matt, Sarah M. and Haschke, John M. and McLean, William and Dinh, Long N.},

  abstractNote = {Lithium hydride (LiH) is a unique, ionic compound with applications in a variety of industries. Unfortunately, LiH is very reactive toward H2O even at ppm levels, forming oxide (Li2O) and hydroxide (LiOH) corrosion layers while outgassing H2. An effective means to eliminate unwanted outgassing is vacuum-heating to convert LiOH into Li2O, although subsequent re-exposure to moisture during transport/handling reconverts some Li2O back to LiOH. A corrosion growth model for previously vacuum-baked LiH is necessary for long-term prediction of the hydrolysis of LiH. In this work, a para-linear hydroxide corrosion growth model is proposed for the reaction of previously vacuum-baked LiH samples with moisture. This model, composed of two competing diffusion reaction fronts at the LiOH/Li2O and Li2O/LiH interfaces, is validated experimentally by subjecting a previously vacuum-baked polycrystalline LiH sample to 35 ppm of H2O at room temperature while monitoring the corrosion growth as a function of time with diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. The para-linear growth model for the hydrolysis of previously vacuum-baked LiH proposed in this report can also serve as a template for the hydrolysis of other hygroscopic oxides grown on metal or metal hydride substrates.},

  doi          = {10.1021/acs.jpca.9b09951},

  journal      = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},

  number       = 2,

  volume       = 124,

  place        = {United States},

  year         = {2019},

  month        = {12}

}

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