Oxide-Scale and α-Casing Characterization in Ti6Al4V Alloy Oxidised in Oxygen Gas

2006 ◽  
Vol 43 (11) ◽  
pp. 559-574
Author(s):  
M. N. Mungole ◽  
M. Surender ◽  
S. Bhargava
Keyword(s):  
Oxide Scale ◽  
Ti6al4v Alloy ◽  
Oxygen Gas

Influence of Water Vapor on Oxide Scale Morphology of Incoloy800HT at 850°C

2018 ◽  
Vol 875 ◽  
pp. 36-40 ◽  
Author(s):  
Anusara Srisrual ◽  
Kasidet Pitaksakorn ◽  
Piyorose Promdirek
Keyword(s):  
Raman Spectroscopy ◽  
Water Vapor ◽  
Oxide Scale ◽  
Surface Finishing ◽  
Scale Morphology ◽  
Spinel Oxide ◽  
Thermal Oxide ◽  
Influence Of Water ◽  
Oxide Phases ◽  
Oxygen Gas

This paper aims to report the influence of water vapor on thermal oxide scale grown on incoloy800HT at 850°C. Alloy was prepared in coupons with a surface finishing up to 1200 SiC abrasive paper. Oxidization was performed in tubular furnace at 850°C during 50 hours. The oxidizing gases were varied as a dry oxygen gas and a wet oxygen gas. Thermal oxide morphology was characterized by scanning electron microscopy (SEM). Oxide phases were identified by X-ray diffraction (XRD) and Raman spectroscopy techniques. The oxide multilayers were revealed in all the oxidized samples. Oxide spallation was obviously detected on the samples oxidized under a dry oxygen gas, whereas, the spallation was not detected on the samples oxidized under a wet oxygen gas. Moreover, by water vapor mixing gas, the alloy surface presented a finer oxide. XRD and Raman spectroscopy provided the coincident oxide identification results. The corundum oxide of (Fe,Cr)2O3and the spinel oxide of (Fe,Cr)3O4were identified as a typical thermal oxide, however, the oxides were different in stoichiometry. The existence of water vapor promoted a Cr2O3corundum oxide, whereas, a Fe3O4spinel oxide was hindered from the outer oxide layer. Hence, water vapor not only clearly influenced on oxide scale morphology but also affected on stoichiometry of (Fe,Cr)2O3and (Fe,Cr)3O4solid solution.

Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

1970 ◽  
Vol 28 ◽  
pp. 510-511
Author(s):  
L. P. Lemaire ◽  
D. E. Fornwalt ◽  
F. S. Pettit ◽  
B. H. Kear
Keyword(s):  
Oxide Scale ◽  
Oxidation Process ◽  
Short Circuit ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Thin Oxide Films ◽  
Diffusion Paths ◽  
Oxidation Resistant ◽  
Structural Imperfections ◽  
Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

The effect of water vapor in increasing growth stresses in the oxide scale on martensitic steam plant alloys

2005 ◽  
Vol 22 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Alexander Donchev ◽  
Harald Fietzek ◽  
Vladislav Kolarik ◽  
Daniel Renusch ◽  
Michael Schütze
Keyword(s):  
Water Vapor ◽  
Oxide Scale ◽  
Growth Stresses ◽  
Effect Of Water ◽  
Steam Plant

Structure and tribocorrosion properties of duplex treatment coatings of TiSiCN/nitride on Ti6Al4V alloy

2019 ◽  
Vol 45 (9) ◽  
pp. 12461-12468 ◽  
Author(s):  
Minpeng Dong ◽  
Yebiao Zhu ◽  
Chunting Wang ◽  
Lei Shan ◽  
Jinlong Li
Keyword(s):  
Ti6al4v Alloy ◽  
Duplex Treatment
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