On the use of AES data analysis to determine local enrichments of conversion coating elements at intermetallic particles on rolled Al

Abstract Additively manufactured (AM) AlSi10Mg is one of the most studied AM aluminium alloys to date. While several studies have focused on investigating its mechanical properties and corrosion performance, very little work has been dedicated to study corrosion protection mechanisms and surface treatments applicable for this material. This work presents for the first time an analysis of the mechanism of Zr electrochemical conversion on AM AlSi10Mg parts. A comparison with the conventional cast alloy was also conducted. An analysis of the specimens using SEM/EDS provided interesting insights concerning the effect of the microstructure on the deposition of the Zr conversion layer. This work demonstrates that due to the very fine microstructure and distribution of alloying elements in AM AlSi10Mg, a homogeneous deposition of the Zr conversion layer is promoted. Conversely, the cast alloy is characterized by a very heterogeneous deposition of the Zr conversion layer due to the presence of relatively large Fe-containing intermetallic particles. The influence of the conversion coating on the corrosion performance of these materials was also studied. The results show that while the conversion treatment has no impact on the corrosion resistance of the cast alloy, it greatly improves the passivity of the AM AlSi10Mg samples.

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A Study of the Localized Ceria Coating Deposition on Fe-Rich Intermetallics in an AlSiFe Cast Alloy

Materials ◽

10.3390/ma14113058 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3058

Author(s):

Salil Sainis ◽

Caterina Zanella

Keyword(s):

Aluminium Alloys ◽

Cast Alloy ◽

Conversion Coating ◽

Precipitation Reaction ◽

Coating Solution ◽

Intermetallic Particles ◽

Short Period ◽

Coating Formation ◽

Work Model ◽

Galvanic Couples

Corrosion inhibiting conversion coating formation is triggered by the activity of micro-galvanic couples in the microstructure and subsequent local increase in pH at cathodic sites, which in the case of aluminium alloys are usually intermetallics. Ceria coatings are formed spontaneously upon immersion of aluminium alloys in a cerium conversion coating solution, the high pH gradient in the vicinity of intermetallics drives the local precipitation of ceria conversion compounds. Cu-rich intermetallics demonstrate a highly cathodic nature and have shown the local precipitation reaction to occur readily. Fe-rich intermetallics are, however, weaker cathodes and have shown varied extents of localized deposits and are in focus in the current work. Model cast Al-7wt.%Si alloys have been designed with 1 wt.% Fe, solidified at different cooling rates to achieve two different microstructures, with big and small intermetallics, respectively. Upon subjecting the two microstructures to the same conversion coating treatment (immersion in a 0.1 M CeCl3 solution) for a short period of 2 h, preferential heavy deposition on the boundaries of the big intermetallics and light deposition on the small intermetallics was observed. Based on these observations, a mechanism of localized coating initiation at these Fe-rich intermetallic particles (IM) is proposed.

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Microchemical imaging in biomedical research

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130225 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1118-1119

Author(s):

P. Ingram

Keyword(s):

Data Analysis ◽

Electron Probe ◽

The Other ◽

X Ray ◽

Cell Element ◽

Physiological Information ◽

Functional States ◽

Elemental Maps ◽

Electron Energy Loss ◽

Secondary Ion

It is well established that unique physiological information can be obtained by rapidly freezing cells in various functional states and analyzing the cell element content and distribution by electron probe x-ray microanalysis. (The other techniques of microanalysis that are amenable to imaging, such as electron energy loss spectroscopy, secondary ion mass spectroscopy, particle induced x-ray emission etc., are not addressed in this tutorial.) However, the usual processes of data acquisition are labor intensive and lengthy, requiring that x-ray counts be collected from individually selected regions of each cell in question and that data analysis be performed subsequent to data collection. A judicious combination of quantitative elemental maps and static raster probes adds not only an additional overall perception of what is occurring during a particular biological manipulation or event, but substantially increases data productivity. Recent advances in microcomputer instrumentation and software have made readily feasible the acquisition and processing of digital quantitative x-ray maps of one to several cells.

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Microanalytical Identification of a New Zr-Nb-Fe Phase

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134259 ◽

1990 ◽

Vol 48 (2) ◽

pp. 132-133

Author(s):

O.T. Woo ◽

G.J.C. Carpenter

Keyword(s):

Trace Elements ◽

Cold Rolling ◽

Proportionality Factor ◽

Tube Material ◽

X Ray ◽

Metal Foils ◽

Arc Melting ◽

Intermetallic Particles ◽

Intermetallic Precipitates ◽

Cold Worked

To study the influence of trace elements on the corrosion and hydrogen ingress in Zr-2.5 Nb pressure tube material, buttons of this alloy containing up to 0.83 at% Fe were made by arc-melting. The buttons were then annealed at 973 K for three days, furnace cooled, followed by ≈80% cold-rolling. The microstructure of cold-worked Zr-2.5 at% Nb-0.83 at% Fe (Fig. 1) contained both β-Zr and intermetallic precipitates in the α-Zr grains. The particles were 0.1 to 0.7 μm in size, with shapes ranging from spherical to ellipsoidal and often contained faults. β-Zr appeared either roughly spherical or as irregular elongated patches, often extending to several micrometres.The composition of the intermetallic particles seen in Fig. 1 was determined using Van Cappellen’s extrapolation technique for energy dispersive X-ray analysis of thin metal foils. The method was employed to avoid corrections for absorption and fluorescence via the Cliff-Lorimer equation: CA/CB = kAB · IA/IB, where CA and CB are the concentrations by weight of the elements A and B, and IA and IB are the X-ray intensities; kAB is a proportionality factor.

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Perceptions of a Collaborative Professional Learning Program: Seeing the “Bigger Picture”

Perspectives of the ASHA Special Interest Groups ◽

10.1044/2019_persp-19-00041 ◽

2020 ◽

Vol 5 (1) ◽

pp. 290-303

Author(s):

P. Charlie Buckley ◽

Kimberly A. Murza ◽

Tami Cassel

Keyword(s):

Data Analysis ◽

Professional Learning ◽

Social Communication ◽

Special Educators ◽

Service Providers ◽

Integrative Approach ◽

Theory Approach ◽

Learning Program ◽

Speech Language Pathologists ◽

Related Service

Purpose The purpose of this study was to explore the perceptions of special education practitioners (i.e., speech-language pathologists, special educators, para-educators, and other related service providers) on their role as communication partners after participation in the Social Communication and Engagement Triad (Buckley et al., 2015 ) yearlong professional learning program. Method A qualitative approach using interviews and purposeful sampling was used. A total of 22 participants who completed participation in either Year 1 or Year 2 of the program were interviewed. Participants were speech-language pathologists, special educators, para-educators, and other related service providers. Using a grounded theory approach (Glaser & Strauss, 1967 ) to data analysis, open, axial, and selective coding procedures were followed. Results Three themes emerged from the data analysis and included engagement as the goal, role as a communication partner, and importance of collaboration. Conclusions Findings supported the notion that educators see the value of an integrative approach to service delivery, supporting students' social communication and engagement across the school day but also recognizing the challenges they face in making this a reality.

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Communicative Performance of Adolescents with Severe Speech Impairment

Journal of Speech and Hearing Disorders ◽

10.1044/jshd.5403.403 ◽

1989 ◽

Vol 54 (3) ◽

pp. 403-421 ◽

Cited By ~ 7

Author(s):

Beth M. Dalton ◽

Jan L. Bedrosian

Keyword(s):

Data Analysis ◽

Peer Interactions ◽

Consistent Pattern ◽

Clinical Implications ◽

Speech Impairment ◽

Communication Mode ◽

Mode Function ◽

Communicative Performance ◽

Therapy Room ◽

Communication Board

The communicative performance of 4 preoperational-level adolescents, using limited speech, gestures, and communication board techniques, was examined in a two-part investigation. In Part 1, each subject participated in an academic interaction with a teacher in a therapy room. Data were transcribed and coded for communication mode, function, and role. Two subjects were found to predominantly use the speech mode, while the remaining 2 predominantly used board and one other mode. The majority of productions consisted of responses to requests, and the initiator role was infrequently occupied. These findings were similar to those reported in previous investigations conducted in classroom settings. In Part 2, another examination of the communicative performance of these subjects was conducted in spontaneous interactions involving speaking and nonspeaking peers in a therapy room. Using the same data analysis procedures, gesture and speech modes predominated for 3 of the subjects in the nonspeaking peer interactions. The remaining subject exhibited minimal interaction. No consistent pattern of mode usage was exhibited across the speaking peer interactions. In the nonspeaking peer interactions, requests predominated. In contrast, a variety of communication functions was exhibited in the speaking peer interactions. Both the initiator and the maintainer roles were occupied in the majority of interactions. Pertinent variables and clinical implications are discussed.

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