Ultrafine-grained surface layer on Mg–Al–Zn alloy produced by cryogenic burnishing for enhanced corrosion resistance

2011 ◽  
Vol 65 (6) ◽  
pp. 520-523 ◽  
Author(s):  
Z. Pu ◽  
S. Yang ◽  
G.-L. Song ◽  
O.W. Dillon ◽  
D.A. Puleo ◽  
...  
2013 ◽  
Vol 706-708 ◽  
pp. 78-81 ◽  
Author(s):  
D.R. Fang ◽  
F.F. Liu ◽  
Chun Liu

Cu-32wt.%Zn alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy decreases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the sample subjected to ECAP can be further improved by relief annealing.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 567
Author(s):  
Paulina Kowalczyk ◽  
Konrad Dybowski ◽  
Bartłomiej Januszewicz ◽  
Radomir Atraszkiewicz ◽  
Marcin Makówka

This paper presents the concept of modification of physicochemical properties of steels by simultaneous diffusion saturation with carbon and chromium or aluminum. The application of a hybrid surface treatment process consisting of a combination of aluminizing and low-pressure carburizing (Al + LPC) resulted in a reduction in the amount of retained austenite in the surface layer of the steel. While the use of chromium plating and low-pressure carburizing (Cr + LPC) induced an improvement in the corrosion resistance of the carburized steels. It is of particular importance in case of vacuum processes after the application of which the active surface corrodes easily, as well as in case of carburizing of low-alloy steel with nickel, where an increased content of retained austenite in the surface layer is found after carburizing.


2013 ◽  
Vol 803 ◽  
pp. 226-229
Author(s):  
Da Ran Fang ◽  
Chun Liu ◽  
Feng Fang Liu

Al-3.9wt.%Cu alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy increases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the alloy subjected to ECAP can be improved by relief annealing.


1988 ◽  
Vol 125 ◽  
Author(s):  
J-P. Hirvonen ◽  
R.O. Toivanen ◽  
V.K. Lindroos

ABSTRACTSelective corrosion resistance of the chromium implanted brass as well as vacancy formation were investigated. Dealloying was observed to create excess vacancies. Chromium and boron and many other potentially beneficial alloying elements like C, N, Si, P, V, Co, Ni, Cu, Ge, As, Y, Nb, Pd, Ag, Sn, Sb, have a repulsive interaction with vacancies and they could increase the dezincification resistance in alpha brass but not in beta brass. Boron implanted brass was found to be more resistant to selective corrosion than the chromium implanted brass.


2021 ◽  
Vol 122 (8) ◽  
pp. 761-767
Author(s):  
V. N. Chuvil’deev ◽  
A. V. Nokhrin ◽  
P. V. Andreev ◽  
N. G. Sandler ◽  
A. M. Bakmetyev ◽  
...  

Author(s):  
Taha Mattar ◽  
Ehab Abdel Rahman ◽  
Ahmed Abdel-Aziz ◽  
Haytham El-Gazzar

Aluminum is one of most common metals in all advanced and modern scientific and technological applications including electrical, electronic, chemical, engineering, energy and medical fields. The performance of aluminum alloys determines to large extent the quality and economic status of the different processes. Aluminum surface structure determine its performance where nano sized grains and layer can improve aluminum properties and performance. In this work, the improvement of aluminum surface structure and formation of nano structured surface grains by laser surface melting (LSM) using Nd-YAG laser under argon atmosphere was investigated. Different power and scanning speed were applied. The physical and chemical properties of the produced surfaces were examined. SEM, EDX and XRD analyses were performed and were correlated to hardness results. Corrosion resistance of the treated surface was investigated to evaluate their performance in aggressive media and chemical and medical applications. From the obtained data it can be concluded that Nd-YAG laser surface melting of aluminum results in formation of 750 micron nano-structured surface layer. Adjustment of LSM parameters could produce 100 nm grains or less. The obtained results showed also that LSM under argon can eliminate the formation of Al2O3 surface layer which may deteriorates the performance in certain applications. Surface layer rich in AlN is formed upon LSM. It was concluded also that corrosion resistance of the treated aluminum surfaces was improved to large extent by LSM.


Author(s):  
Do Le Hung Toan, Shuo-Jen Lee Do

Micro arc oxidation method has been developed in the field of surface protection of magnesium alloys and considered as a simple, highly effective, commercial and environmentally friendly method in industry. MAO coatings are fabricated on novel Mg-Al-Li-Zn alloy to improve the anti-corrosion performance of surface by using friendly alkaline electrolytes under a high electrical potential. The Taguchi method and optimal analysis are used to identify the effects of the three factors including current density, processing time and electrical frequency on coating’s characteristics. The results have shown that the main factor that affects coating thickness and corrosion resistance of coating is the processing time. The results obtained by optimal conditions are consistent with prediction values of Taguchi analysis. The thickness of the coating can help to improve the long-term corrosion protection of a MAO coating in corrosive environments.


2012 ◽  
Vol 727-728 ◽  
pp. 1238-1242 ◽  
Author(s):  
Roger Borges ◽  
Antônio Carlos da Silva ◽  
Juliana Marchi

Among bioceramics materials, bioglasses which exhibits either a bioactive or resorbable behavior has been studied for many applications, such as bone substitutive and regeneration. When in contact with body fluid, the bioglasses can induce the formation of a hydroxyapatite surface layer. In this paper, we studied the bioactivity of a bioglass containing 48 wt %SiO2, 27 wt% Na2O, 19 wt % CaO and 6 wt %P2O5. After fusion and annealing, the samples were immersed in SBF for different periods, up to 14 days. The samples were characterized through XRD, DRIFT and SEM before and after bioactivity experiments. The overall results suggest the formation of a surface layer of consisting of hydroxyapatite, which was crystallized within seven days after in vitro experiments, leading to a suitable bioactivity. Moreover, the samples showed a glass network with high cohesion due to calcium addition, leading to materials with high corrosion resistance.


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