The Role of Alloy Composition on the Steam Oxidation Resistance of 9-12%Cr Steels

2006 ◽  
Vol 522-523 ◽  
pp. 129-138 ◽  
Author(s):  
Stephen Osgerby ◽  
A. Tony Fry
Keyword(s):  
Oxide Layer ◽  
Defect Structure ◽  
Alloy Composition ◽  
Steam Oxidation ◽  
Oxide Scales ◽  
Martensitic Steels ◽  
Minor Elements ◽  
Composition Modification ◽  
Gas Penetration

Three commercial martensitic steels have been oxidised in steam at 600 and 650 °C for times up to 10000 h. The partition of minor elements within the oxide scales has been determined. Silicon forms an additional oxide layer beneath the spinel. Chromium, molybdenum and tungsten concentrate in the spinel and manganese is present in both the spinel and magnetite. Several proposed mechanisms for steam oxidation have been examined to explain the observed effects of alloy composition. Modification of the oxide defect structure and oxidant gas penetration through microcracks were identified as the mechanisms most able to explain the influence of alloy composition.

Steam Oxidation of Creep-Strength Enhanced 9Cr Ferritic Steel: Void Formation in Oxide Scale and Its Relation to Scale Exfoliation

2004 ◽  
Author(s):  
Yutaka Watanabe ◽  
Hiroaki Kikkawa
Keyword(s):  
Ferritic Steel ◽  
Superheated Steam ◽  
Void Formation ◽  
Tensile Tests ◽  
Steam Oxidation ◽  
Oxide Scales ◽  
Void Distribution ◽  
Boiler Tubes ◽  
Fossil Power Plant

The purposes of this research are (1) evaluating the importance of voids existing in oxide scales to exfoliation of oxide scales formed in superheated steam, (2) discussing possible role of Cr-rich layer in void formation in the oxide scales. First, superheater tubes, which are made of 9Cr-1MoVNb ferritic steel and were experienced with scale exfoliation, were removed from a fossil power plant and oxidation interfaces of the boiler tubes were examined in terms of structure, void distribution, elemental profile of the oxide scales and exfoliation characteristics. Then, exfoliation behaviors of oxide scales were evaluated on actual superheater tubes and on the steam oxidation specimens experimentally oxidized in autoclaves by tensile tests in terms of exfoliation strength and of position of exfoliation and its relation with void distribution in the scales. The results indicated an important role of void formation and growth in exfoliation of scale exfoliation. Void formation mechanism was also discussed based on the observed characteristics of the oxide scales.

Applications of Energy Beams in Material and Device Processing

1983 ◽  
Vol 23 ◽  
Author(s):  
G.J. Galvin ◽  
L.S. Hung ◽  
J.W. Mayer ◽  
M. Nastasi
Keyword(s):  
Ion Beam ◽  
High Energy ◽  
Ion Beams ◽  
Traditional Role ◽  
Near Surface ◽  
Device Processing ◽  
Composition Modification ◽  
Directed Energy ◽  
Transistor Fabrication

ABSTRACTEnergetic ion beams used outside the traditional role of ion implantation are considered for semiconductor applications involving interface modification for self-aligned silicide contacts, composition modification for formation of buried oxide layers in Si on insulator structures and reduced disorder in high energy ion beam annealing for buried collectors in transistor fabrication. In metals, aside from their use in modification of the composition of near surface regions, energetic ion beams are being investigated for structural modification in crystalline to amorphous transitions. Pulsed beams of photons and electrons are used as directed energy sources in rapid solidification. Here, we consider the role of temperature gradients and impurities in epitaxial growth of silicon.

Study of the Role of Small Additions of Zr in the CVD- FBR Aluminization Process

2009 ◽  
Vol 289-292 ◽  
pp. 293-300
Author(s):  
L. Sánchez ◽  
F.J. Bolívar ◽  
M.P. Hierro ◽  
F.J. Pérez
Keyword(s):  
Fluidized Bed ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Fluidized Bed Reactor ◽  
Iron Aluminide ◽  
Martensitic Steels ◽  
Aluminide Coatings ◽  
Deposition Parameters ◽  
Zirconium Powder

In this work, iron aluminide coatings were developed by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic-martensitic steels. Small additions of zirconium powder were introduced in the fluidized bed; as a consequence, the obtained coatings are thicker than that without zirconium additions. When Zr powders are added in the fluidized bed, the deposition atmosphere drastically changes, leading to increase the deposition rate. Thermodynamic calculations were carried out to simulate the modifications in the CVD atmosphere in the Al/Zr deposition system in comparison to the single aluminization. In order to optimize the conditions of the deposition, parameters such as temperature and concentration of zirconium introduced into the bed were evaluated and compared with the results obtained for the single aluminum deposition.

Role of grain boundary engineered microstructure on high temperature steam oxidation behaviour of Ni based superalloy alloy 617

2019 ◽  
Vol 778 ◽  
pp. 224-233 ◽  
Author(s):  
C.N. Athreya ◽  
K. Deepak ◽  
Dong-Ik Kim ◽  
B. de Boer ◽  
Sumantra Mandal ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Oxidation Behaviour ◽  
Steam Oxidation ◽  
Alloy 617 ◽  
High Temperature Steam

Role of defect structure on hydrogenation properties of Zr 0.9 Ti 0.1 V 2 alloy

2011 ◽  
Vol 36 (15) ◽  
pp. 9318-9323 ◽  
Author(s):  
X.W. Yang ◽  
J.S. Li ◽  
T.B. Zhang ◽  
R. Hu ◽  
X.Y. Xue ◽  
...  
Keyword(s):  
Defect Structure

Surface Defects in Drawn Aluminum Magnet Wire

1975 ◽  
Vol 97 (1) ◽  
pp. 134-141 ◽  
Author(s):  
R. N. Wright ◽  
A. T. Male
Keyword(s):  
Defect Structure ◽  
Surface Characterization ◽  
Surface Defect ◽  
Potential Role ◽  
Surface Defects ◽  
Repair Process ◽  
Fine Surface ◽  
Magnet Wire ◽  
Characterization Studies

The fine surface defect structure of commercial EC grade aluminum magnet wire has been characterized and four basic component types have been identified. A grading system has been established for each of the component defects. Intermediate process surface characterization studies and laboratory drawing experiments have been performed to clarify the origin of the defects. The potential role of drawing lubrication in repairing or compounding the defect structure has been demonstrated and the mechanics of a drawing related repair process have been clarified through study of the effects of rod drawing on hardness indentations.

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