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Materials assurance through orthogonal materials measurements: X-ray fluorescence aspects

Powder Diffraction

Rodriguez, Mark A.; Van Benthem, Mark V.; Susan, D.F.; Griego, James J.M.; Yang, Pin Y.; Mowry, Curtis D.; Enos, David E.

X-ray fluorescence (XRF) has been employed as one of several orthogonal means of screening materials to prevent counterfeit and adulterated products from entering the product stream. We document the use of principal component analysis (PCA) of XRF data on compositionally similar and dissimilar stainless steels for the purpose of testing the feasibility of employing XRF spectra to parse and bin these alloys as the same or significantly different alloy materials. The results indicate that XRF spectra can separate and assign alloys via PCA, but that important corrections for detector drift and scaling must be performed in order to achieve valid results.

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TYPE Conference Poster YEAR 2017
ScopusOSTIDOI

Monitoring of CoS2 reactions using high-temperature XRD coupled with gas chromatography (GC)

Powder Diffraction

Rodriguez, Mark A.; Coker, Eric N.; Griego, James J.M.; Mowry, Curtis D.; Pimentel, Adam S.; Anderson, Travis M.

High-temperature X-ray diffraction with concurrent gas chromatography (GC) was used to study cobalt disulfide cathode pellets disassembled from thermal batteries. When CoS2 cathode materials were analyzed in an air environment, oxidation of the K(Br, Cl) salt phase in the cathode led to the formation of K2SO4 that subsequently reacted with the pyrite-type CoS2 phase leading to cathode decomposition between ∼260 and 450 °C. Independent thermal analysis experiments, i.e. simultaneous thermogravimetric analysis/differential scanning calorimetry/mass spectrometry (MS), augmented the diffraction results and support the overall picture of CoS2 decomposition. Both gas analysis measurements (i.e. GC and MS) from the independent experiments confirmed the formation of SO2 off-gas species during breakdown of the CoS2. In contrast, characterization of the same cathode material under inert conditions showed the presence of CoS2 throughout the entire temperature range of analysis.

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TYPE Journal Article YEAR 2016
ScopusOSTIDOI
Results 26–50 of 101
Results 26–50 of 101