scholarly journals The Growing Process of Oxide Film on Al-Mg Alloy in Pure Water at Low Temperatures

1996 ◽  
Vol 45 (10) ◽  
pp. 609-613
Author(s):  
Reiko Shiozawa ◽  
Kyoichi Oki ◽  
Susumu Arai
Keyword(s):  
Oxide Film ◽  
Low Temperatures ◽  
Pure Water ◽  
Mg Alloy

scholarly journals Effects of transition metal additions on double-oxide film defects in an Al–Si–Mg alloy

2017 ◽  
Vol 33 (18) ◽  
pp. 2212-2222 ◽  
Author(s):  
W. D. Griffiths ◽  
A. J. Caden ◽  
Qi Chen
Keyword(s):  
Transition Metal ◽  
Oxide Film ◽  
Mg Alloy ◽  
Double Oxide

Oxide scale behavior of Al–7.5 mass%Mg alloy containing trace Ca during short-term oxidation

2021 ◽  
Vol 11 (11) ◽  
pp. 1881-1886
Author(s):  
Seong-Ho Ha ◽  
Young-Ok Yoon ◽  
Bong-Hwan Kim ◽  
Hyun-Kyu Lim ◽  
Sung-Hwan Lim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Oxide Film ◽  
Phase Diagrams ◽  
Film Formation ◽  
Mg Alloy ◽  
Short Term ◽  
Spinel Formation ◽  
Transmission Electron ◽  
Significant Difference

In this study, using transmission electron microscopy and phase diagrams from thermodynamic calculations, we investigated the oxide film formation of Al–7.5 mass%Mg alloy containing Ca traces during short-term oxidation in terms of the thermodynamic stability and multi-element oxides by inter-diffusion based on the results of analysis for the oxide film. For the oxidation test at 515 ˚C, for 1 h, its results showed that there is no significant difference between the Ca-added and Ca-free Al–7.5 mass%Mg alloys was observed, while further exposure caused the Ca-free alloy to gain significant weight. Based on the standard Gibbs free energy for oxide production calculated in this study, CaO was the most preferential product among the single metal oxides examined. As per calculations for MgAl2O4-spinel formation reactions, the spinel formation from MgO was thermodynamically the most favorable. According to the phase diagrams calculated in this study, various multi-element oxides including Ca could possibly form in the oxide layer of Ca-added alloy. The analysis results of transmission electron microscopy confirmed that MgO is the primary oxide in the Al–Mg binary alloys. In oxidation tests conducted for less than 1 h, the spinel was rarely found. The outmost areas of oxide layers correspond to MgO and CaO in Ca-free and Ca-added alloys, respectively. However, in the Ca-added alloy, the inner layer contains certain amounts of Ca, Al, and Mg.

Effects of Environmental Factors on the Electronic Properties of Interfacial Oxide Film on 304L Stainless Steel in High Temperature Pure Water

2004 ◽  
Vol 261-263 ◽  
pp. 919-924 ◽  
Author(s):  
Zhan Peng Lu ◽  
Yo-ichi Takeda ◽  
Tetsuo Shoji
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Oxide Film ◽  
Electronic Properties ◽  
Pure Water ◽  
Oxide Films ◽  
304L Stainless Steel ◽  
Film Properties ◽  
High Temperature Water ◽  
Temperature Water

The electronic properties of the interfacial oxide film formed on 304L stainless steel in high temperature water are investigated by contact electric resistance (CER) measurements. Tests are performed in pure water with a wide range of dissolved oxygen (DO) content at 200, 250, and 288°C. The electrochemical potential (ECP) moves in the noble direction and CER increases when increasing DO. Results show that DO content has a dominant effect on the electronic properties of oxide film. The change of oxide film properties can also be attributed to the variation of the electrochemical potential, which is directly affected by DO content. Critical potentials exist for the formation and reduction of oxide films in high temperature water. Multiple steps are found for the reduction of oxide films due to de-aeration in 200, 250, and 288°C water, implying the presence of multiple-layer interfacial oxide films. The film reduction process is relatively slower than the film formation process. Present results show that even in high purity water, a moderate change of DO content can result in different surface conditions. Dissolved hydrogen has a moderate effect on interfacial surface films in deaerated water. In-situ monitoring of the oxide film properties by CER technique provides information on the interfacial reactions that are related to the SCC behavior of materials in high temperature water environments.

The Effects of Hydrogen on Properties of Surface Films Formed on Iron in Sulfate Solutions

2014 ◽  
Vol 936 ◽  
pp. 1120-1124 ◽  
Author(s):  
Ahsan Ejaz ◽  
Zhan Peng Lu ◽  
Jun Jie Chen ◽  
Xiao Feng Xia ◽  
Qian Xiao ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Oxide Film ◽  
Open Circuit Potential ◽  
Pure Water ◽  
Open Circuit ◽  
Surface Films ◽  
Concentrated Solutions ◽  
Sulfate Solutions ◽  
Corrosion Of Iron

The effects of charged hydrogen in iron on surface properties of iron in pure water and sodium sulfate solutions of various concentrations were investigsted by open circuit potential monitoring, surface morphology observations, Raman spectroscopy and XRD measurements. Hydrogen in iron shifed the open circuit potential in the negative directions. Hydrogen could change the types of oxide film on iron. Effects of hydrogen on corrosion of iron was More significant in pure water and dilute sodium solutions than those in concentrated solutions.

scholarly journals The Oxidation of Copper in Air at Temperatures up to 100 °C

2021 ◽  
Vol 2 (4) ◽  
pp. 625-640
Author(s):  
Jari Aromaa ◽  
Marko Kekkonen ◽  
Mehrdad Mousapour ◽  
Ari Jokilaakso ◽  
Mari Lundström
Keyword(s):  
Oxide Film ◽  
Weight Change ◽  
Low Temperatures ◽  
Quartz Crystal ◽  
Copper Film ◽  
Copper Surface ◽  
Copper Sample ◽  
Oxide Film Thickness ◽  
Xrd Patterns ◽  
Kinetics Of

The aim of this study was to investigate the oxidation kinetics of copper at low temperatures (60 °C to 100 °C) in air by isothermal thermogravimetric analysis (TGA) and quartz crystal microbalance (QCM). The weight change in thermogravimetric tests showed periodic weight increase and decrease. In thermogravimetric tests the mass of the copper sample increased until the oxidation gradually slowed down and finally started to decrease due to cracking and spalling of the oxide formed on the surface. In QCM tests using electrodeposited copper film, the weight change was rapid at the beginning but slowed to a linear relationship after few minutes. Temperature and exposure time appeared to have a large effect on oxide film thickness and composition. With QCM, oxidation at 60–80 °C produced less than 40 nm films in 10 days. Oxidation at 90–100 °C produced 40 nm thick films in a day and over 100 nm films in a week. Although SEM-EDS analyses in TGA tests indicated that oxygen was adsorbed on the copper surface, neither XRD patterns nor Raman spectroscopy measurements showed any trace of Cu2O or CuO formation on the copper surface. Electrochemical reduction analysis of oxidized massive copper samples indicated that the oxide film is mostly Cu2O, and CuO develops only after several days at 90–100 °C.

Effects of Charged Hydrogen on Oxidation Behavior of Alloy 690 in High Temperature Water Environments

2017 ◽  
Author(s):  
Hao Peng ◽  
Zhanpeng Lu ◽  
Xiangkun Ru ◽  
Junjie Chen ◽  
Jiarong Ma ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Oxidation Behavior ◽  
Pure Water ◽  
Water Environment ◽  
Oxide Films ◽  
High Temperature Water ◽  
Alloy 690 ◽  
Temperature Water

The oxide films formed on non-charged and hydrogen-charged Alloy 690 specimens exposed to 290 °C pure water environment with different dissolved oxygen concentrations were characterized. It was found that the oxide film formed on the hydrogen-charged specimen was thicker than that on the noncharged specimen. Local protruding oxides were observed on the hydrogen-charged Alloy 690 but not on the non-charged specimen. The Ni and Fe contents of local protrusion on the hydrogen-charged specimen were higher than those on the noncharged specimen.

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