TEM Investigation of the Microstructure of the Scale Formed on a FeCrAlRE Alloy at 900 °C: The Effect of Y-rich RE Particles

Liu, Fang; Götlind, Helena; Svensson, Jan‐Erik; Johansson, Lars‐Gunnar; Halvarsson, Mats

doi:10.1007/s11085-010-9195-5

Cited by 28 publications

(11 citation statements)

References 40 publications

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“…Another precipitate showed very little Al content (EDS 3). A similar formation of two types of Yrich particles was noted previously [14,15]. In general, the precipitates were more uniform in size and distribution in dry O 2 compared to wet air and Ar þ 10%H 2 O at 1050 C. The average alumina grain size formed at the surface in dry O 2 at 1050 C increased from 0.14 mm at 1 h to 0.3 mm at 500 h, showing some grain growth with exposure time.…”

Section: Resultssupporting

confidence: 81%

Effect of environment on the scale formed on oxide dispersion strengthened FeCrAl at 1050°C and 1100°C

Unocic

Essuman

Dryepondt

et al. 2012

Materials at High Temperatures

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The surface scale formed on specimens of a commercial oxide dispersion strengthened (ODS) FeCrAl alloy (PM2000 2 ) exposed for 1 and 500 h at 1050 C in dry O 2 , Air þ 10%H 2 O and Ar þ 10%H 2 O consisted of a two-layer a-Al 2 O 3 structure with a columnar grain inner layer and a finer grain outer layer. The alumina scales formed in Air þ 10%H 2 O and Ar þ 10%H 2 O were slightly more than half of the thickness of the scale formed in dry O 2 . The same two-layer structure was also observed after exposure for 500 h at 1100 C in dry O 2 and 50%CO 2 þ 50%H 2 O. The alumina scales formed in both atmospheres were similar in thickness. Oxides rich in Y and Ti at the gas -scale interface grew in size and number with time in each case. Using analytical transmission electron microscopy, alumina grain boundary segregation of both Y and Ti was evident near the gas interface but only Y segregation was detected near the metal interface. This difference was attributed to Ti depletion in the adjacent metal and the rapid outward flux of the smaller Ti ion through the scale.

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Section: Resultssupporting

confidence: 81%

Effect of environment on the scale formed on oxide dispersion strengthened FeCrAl at 1050°C and 1100°C

Unocic

Essuman

Dryepondt

et al. 2012

Materials at High Temperatures

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“…It may be noted that under the same conditions (polished surface, 900°C, O 2 and O 2 ? H 2 O environment), the melt-processed FeCrAl alloy Kanthal Ò AF exhibited significant and continuous outward scale growth [23]. Consequently, outward scale growth appears to be more efficiently suppressed on alloy APMT than on alloy AF.…”

Section: Discussionmentioning

confidence: 97%

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

et al. 2015

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Early oxide scale growth on an oxide dispersion strengthened rapidly solidified powder FeCrAl material, Kanthal Ò APMT, was investigated at 900°C in an O 2 ? N 2 and an O 2 ? H 2 O ? N 2 environment for up to 168 h. Gravimetry was used to follow oxide growth and the oxide scale was examined with XRD. Scale morphology was investigated in detail with SEM/EDX, TEM/EDX/CBED. The alloy rapidly formed a protective two-layered a-alumina scale containing oxide nodules. Between the top and bottom alumina layers there was a zone containing chromia-rich particles 5-20 nm in diameter, corresponding to the original sample surface. The alumina scale mainly grew inward after 1 h of oxidation. Alumina scale growth at 900°C was initially somewhat faster in an O 2 ? H 2 O ? N 2 environment than in an O 2 ? N 2 environment.

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“…A Titan 80-300 TEM, operated at 300 kV, was used to analyse the carbonaceous structure in the cross-sections of the CFs. In order to prepare TEM specimens with a thickness of less than 100 nm, the in situ lift-out technique [19] was employed using an FEI Versa 3D workstation, a combined focused ion beam microscope and SEM (FIB/SEM), equipped with an Omniprobe micromanipulator. To protect the very surface of the CF from ion damaging during the specimen preparation procedure, a layer of Pt was deposited with the aid of the gas injection system in the workstation (Figure 2a).…”

Section: 𝜀𝜀 = δ𝐹𝐹 𝑘𝑘mentioning

confidence: 99%

Graphitic microstructure and performance of carbon fibre Li-ion structural battery electrodes

et al. 2018

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Carbon fibres (CFs), originally made for use in structural composites, have also been demonstrated as high capacity Li-ion battery negative electrodes. Consequently, CFs can be used as structural electrodes; simultaneously carrying mechanical load and storing electrical energy in multifunctional structural batteries. To date, all CF microstructural designs have been generated to realise a targeted mechanical property, e.g. high strength or stiffness, based on a profound understanding of the relationship between the graphitic microstructure and the mechanical performance. Here we further advance this understanding by linking CF microstructure to the lithium insertion mechanism and the resulting electrochemical capacity. Different PAN-based CFs ranging from intermediate-to high-modulus types with distinct differences in microstructure are characterised in detail by SEM and HR-TEM and electrochemical methods. Furthermore, the mechanism of Li-ion intercalation during charge/discharge is studied by in situ confocal Raman spectroscopy on individual CFs. RamanG band analysis reveals a Li-ion intercalation mechanism in the high-modulus fibre reminiscent of that in crystalline graphite. Also, the combination of a relatively low capacity of the highmodulus CFs (ca. 150 mAh/g) is shown to be due to that the formation of a staged structure is frustrated by an obstructive turbostratic disorder. In contrast, intermediate-modulus CFs, which have significantly higher capacities (ca. 300 mAh/g), have Raman spectra indicating a Li-ion insertion mechanism closer to that of partly disordered carbons. Based on these findings, CFs with improved multifunctional performance can be realized by tailoring the graphitic order and crystallite sizes.

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TEM Investigation of the Microstructure of the Scale Formed on a FeCrAlRE Alloy at 900 °C: The Effect of Y-rich RE Particles

Cited by 28 publications

References 40 publications

Effect of environment on the scale formed on oxide dispersion strengthened FeCrAl at 1050°C and 1100°C

Effect of environment on the scale formed on oxide dispersion strengthened FeCrAl at 1050°C and 1100°C

The Oxide Scales Formed on a Dispersion-Strengthened Powder Metallurgical FeCrAl Alloy at 900 °C in O2 and in O2 + H2O

Graphitic microstructure and performance of carbon fibre Li-ion structural battery electrodes

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