Local Electrode Atom Probe Tomography

Larson, David J.; Prosa, Ty J.; Ulfig, Robert M.; Geiser, B.; Kelly, Thomas F.

doi:10.1007/978-1-4614-8721-0

Cited by 369 publications

(430 citation statements)

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“…[16][17][18][19][20] APT is able to create atom-by-atom 3D compositional reconstructions of materials within afabricated needle-shaped specimen (tens of nanometers in size), across which ahigh electric field is applied that causes atoms to evaporate during pulsing events.The ions are then spatially detected and their identity determined using time-of-flight mass spectrometry.T his technique has traditionally been used to study conductive materials, [19] but owing to experimental advances,A PT can also now be applied to non-conductive materials.A PT was recently applied to zeolites for the first time to study the distribution of Al atoms in parent and severely steamed, large,coffin-shaped ZSM-5 crystals,where anon-uniform Al distribution was observed. [21] Herein, we report the use of APT to create 3D compositional reconstructions with sub-nm resolution of aZ SM-5 crystal that has been used in the MTH reaction.…”

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Coke Formation in a Zeolite Crystal During the Methanol‐to‐Hydrocarbons Reaction as Studied with Atom Probe Tomography

et al. 2016

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Understanding the formation of carbon deposits in zeolites is vital to developing new,s uperior materials for various applications,i ncluding oil and gas conversion processes.H erein, atom probe tomography (APT) has been used to spatially resolve the 3D compositional changes at the subnm length scale in as ingle zeolite ZSM-5 crystal, whichh as been partially deactivated by the methanol-to-hydrocarbons reaction using 13 C-labeled methanol. The results reveal the formation of coke in agglomerates that span length scales from tens of nanometers to atomic clusters with amedian size of 30-60 13 Ca toms.T hese clusters correlate with local increases in Brønsted acid site density,demonstrating that the formation of the first deactivating coke precursor molecules occurs in nanoscopic regions enriched in aluminum. This nanoscale correlation underscores the importance of carefully engineering materials to suppress detrimental coke formation.Zeolites are crystalline,m icroporous materials that exhibit robust hydrothermal stability,allowing them to be used under demanding process conditions,s uch as oil refinery operations [1,2] and automotive emissions treatments. [3,4] Commercially,one of the most important zeolites is ZSM-5 with MFI framework topology,w hich has become ubiquitous in petroleum refining and chemical manufacturing.[2] Thee normous quantities at which this material is utilized at the global scale continue to drive research targeting improved performance. Thed etrimental formation of coke is one of the factors limiting zeolite materials,p articularly ZSM-5, in highdemand catalytic processes,s uch as fluid catalytic cracking (FCC) and the methanol-to-hydrocarbons (MTH) reaction. ZSM-5 coking in the MTH reaction has long been studied, with ar ange of conclusions regarding the nature and mechanism of coke formation. [5,6] Despite ongoing investigations and debates,there is aconsensus that coking occurs due to the formation of alkylated mono-and polycyclic aromatics near internal channel intersections,followed by an increase in surface coke from polycyclica renes near pore openings, which finally form agraphitic layer and block pore access. [7][8][9][10][11][12][13] In order to more fully elucidate the material properties that promote the detrimental formation of coke during the MTH reaction on ZSM-5, it would be beneficial to study the carbon deposits on the sub-nm length scale.P revious coking studies on ZSM-5 in the MTH reaction have concentrated on the bulk, [7][8][9]13] or on micrometer length scales, [10,11,14,15] to gain some spatial insight, but none have been capable of delivering sub-nm resolution.Theo nly characterization method currently capable of spatially resolving 3D element distributions at the sub-nm scale is atom probe tomography (APT), which was first envisioned in the 1930s,b ut has recently experienced rapid growth due to improvements in instrumentation. [16][17][18][19][20] APT is able to create atom-by-atom 3D compositional reconstructions of materials within afabricated needle-...

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Coke Formation in a Zeolite Crystal During the Methanol‐to‐Hydrocarbons Reaction as Studied with Atom Probe Tomography

et al. 2016

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“…The volume fraction was defined as the ratio of the number of atoms inside the precipitates to the total number of collected atoms. The basic principle of APT and data treatment may be found in different books or reviews [35][36][37][38]. Figure 1 plots both damage and injected Fe concentration profiles obtained under Fe 2+ ion irradiation.…”

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Influence of injected interstitials on α′ precipitation in Fe–Cr alloys under self-ion irradiation

Tissot

Pareige

Meslin

et al. 2016

Materials Research Letters

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“…Nowadays it is a frequently used tool, especially in materials sciences due to its strength in content analysis at the nanometer scale of precipitates, grain boundaries, nano-particles, clusters, and the matrix compositions in three dimensions. [95][96][97] The technique is unique for visualizing and measuring of fine-scaled microstructural (nanostructural) features with near atomic resolution and gaining precise information of compositions in 3D. Especially, where transmission electron microscopy does not produce distinct contrast (e.g., for low alloying element content and elements of similar atomic number, which is the case for AlMgSi alloys [37,98] ), APT is the sole technique for gaining direct insight into the early decomposition of metallic systems.…”

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Clustering in Age‐Hardenable Aluminum Alloys

et al. 2018

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This review gives an overview of the effects of clusters in various aluminum alloys. Characterization methods are discussed in general and results for the important AlMgSi alloys are presented in detail. Indirect characterization methods, such as hardness, tensile testing, electrical resistivity, differential scanning calorimetry, and positron annihilation spectroscopy are discussed, as well as atom probe tomography for the direct measurement of clusters. A particular focus is set on atom probe tomography, where possible artifacts influencing the cluster measurements as well as different cluster finding methods are summed up. A comprehensive summary of investigated alloys and cluster algorithm parameters is given. Moreover, the findings in AlMgSi alloys regarding clusters and changes upon different heat treatments are discussed, starting from early to the latest works. Drawn conclusions are discussed and compared to give a r esum e.

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Local Electrode Atom Probe Tomography

Cited by 369 publications

References 4 publications

Coke Formation in a Zeolite Crystal During the Methanol‐to‐Hydrocarbons Reaction as Studied with Atom Probe Tomography

Coke Formation in a Zeolite Crystal During the Methanol‐to‐Hydrocarbons Reaction as Studied with Atom Probe Tomography

Influence of injected interstitials on α′ precipitation in Fe–Cr alloys under self-ion irradiation

Clustering in Age‐Hardenable Aluminum Alloys

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