Oxide Film Formation at a Microcrystalline Al Alloy in Room Temperature Neutral Borate Solution

1997 ◽  
Vol 144 (2) ◽  
pp. 558-566 ◽  
Author(s):  
S. C. Thomas ◽  
V. I. Birss
1997 ◽  
Vol 144 (4) ◽  
pp. 1353-1361 ◽  
Author(s):  
S. C. Thomas ◽  
V. I. Birss

2018 ◽  
Vol 280 ◽  
pp. 221-225
Author(s):  
C.D. Zuraidawani ◽  
F.W. Norhadira ◽  
Mochd Nazree B. Derman

The Mg-1wt.%Ca alloy was fabricated using powder metallurgy method. The anodizing process were done by using different voltage (5V, 15V, 25V) and concentration of KOH (0.1M, 0.5M, 1.0M). The surface changes on PM Mg/1wt.%Ca resulted by anodizing was analyzed using SEM-EDX and XRD pattern. Meanwhile, surface hardness was measured by micro-Vickers hardness machine. The experiment found different XRD pattern between all non-anodized and anodized samples. The study found that increasing the voltage will increase the hardness while increasing KOH concentration reduced the hardness. The relation of the hardness and oxide film formation can be analyzed using SEM-EDX and XRD pattern. The optimum value for voltage, KOH concentration and hardness are 25V, 0.1M and 27.2 HV. The XRD detect the changes in PM Mg/1wt.% Ca indicates the oxide film formation.


2016 ◽  
Vol 45 (43) ◽  
pp. 17312-17318 ◽  
Author(s):  
Eun-Kyung Kim ◽  
Dasom Park ◽  
Nabeen K. Shrestha ◽  
Jinho Chang ◽  
Cheol-Woo Yi ◽  
...  

An aqueous solution based synthetic method for binder-free Ag2Te thin films using ion exchange induced chemical transformation of Ag/AgxO thin films.


2011 ◽  
Vol 284-286 ◽  
pp. 1665-1670
Author(s):  
Zheng Hua Deng ◽  
Hua Ji Li ◽  
Wei Bin Li

The ZM5-0.1%RE magnesium alloy was heated to 800°C, when the surface oxide film was formed, the ZM5-0.1% RE Magnesium alloy which had being oxidized obtained by removing the surface oxidation film on the ZM5-0.1%RE magnesium alloy at room temperature. TGA curve, oxidaxion kinetics curves at constant temperatuers of the alloy and XRD spectrum of the surface film were analyzed in order to investigate the sureface oxidation behavior.The results show that the alloy still has anti-oxidation performance, And the oxide inerease occurred mostly between 400°C and 700°C,a layer of tight oxide film with 4-5.5um and composed of RE2O3, MgO, Al2O3and Mg17Al12was formed on the surface of magnesiurn alloy. The tight surface oxide film prevented the further oxidation of the base magnesiurn alloy, It show that the regeneration ability of oxidation film on ZM5-0.1%RE Magnesium Alloy was good.


FlatChem ◽  
2021 ◽  
pp. 100317
Author(s):  
Punam Tiwary ◽  
S.G. Chatterjee ◽  
S.S. Singha ◽  
Rajat Mahapatra ◽  
Amit K. Chakraborty

2021 ◽  
Vol 11 (11) ◽  
pp. 1881-1886
Author(s):  
Seong-Ho Ha ◽  
Young-Ok Yoon ◽  
Bong-Hwan Kim ◽  
Hyun-Kyu Lim ◽  
Sung-Hwan Lim ◽  
...  

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.


Author(s):  
T. Saito ◽  
T. Hanasaki ◽  
T. Moriwaki ◽  
T. Goto ◽  
A. Takeda ◽  
...  

1990 ◽  
Vol 213 ◽  
Author(s):  
M. J. Mills ◽  
S. H. Goods ◽  
S. M. Foiles

ABSTRACTThe effect of boron on the structure and macroscopic properties of an isolated grain boundary in bicrystals of a non-stoichiometric Ni3Al alloy (76 at% Ni, 23 at% Al, 1 at%Ta) has been studied. The room temperature tensile ductility and fracture mode of the bicrystals varies dramatically with the rate of cooling after elevated temperature heat treatment. In the absence of significant segregation of boron to the boundary, the bicrystals fail via brittle interfacial fracture with little or no ductility. When the segregation of boron to the boundary is maximized, the bicrystals are highly ductile. High resolution transmission electron microscopy reveals that this ductile state is achieved without the formation of a detectable region of compositional disorder at the boundary. Atomistic calculations using a Monte Carlo scheme predict that only partial disordering of the planes immediately adjacent to the boundary should occur for Ni-rich alloys both with and without boron. These results suggest that the presence of boron causes an increase in the cohesive energy of the boundaries rather than a change in the local compositional ordering.


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