Corrosion Resistance of Mg Alloy with High Zn Concentration Including Impurity Cu

2021 ◽  
Vol 1016 ◽  
pp. 592-597
Author(s):  
Masato Ikoma ◽  
Taiki Morishige ◽  
Tetsuo Kikuchi ◽  
Ryuichi Yoshida ◽  
Toshihide Takenaka

Mg alloys are very attractive materials for transportation industry due to their toughness and lightness. Recycling Mg alloys is desired for energy saving that otherwise would be required to produce its primary metal. However, secondary produced Mg tends to contain a few impurity elements that deteriorate its corrosion resistance. For example, contamination of Mg alloy by Cu induces second phase of Mg2Cu and it works as strong cathode, resulting in the corrosion rate rapidly increasing. It was previously reported that the corrosion resistance of Mg with impurity Cu was remarkably improved by addition of alloying element Zn. Addition of Zn into Mg formed MgZn2 phase and incorporated Cu into MgZn2 phase instead of Mg2Cu formation. In this way, since Zn serves to improve the corrosion resistance of Mg, Mg alloy with high Zn concentration may form a lot of MgZn2 and may have better corrosion resistance even with high Cu concentration. In this work, the corrosion behavior of Mg-6mass%-1mass%Al (ZA61) with different Cu content up to 1mass% was investigated. As a result, ZA61-1.0Cu had much lower corrosion rate compared to Mg-0.2%Cu and the corrosion rate was almost the same as that of pure Mg.

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1188 ◽  
Author(s):  
Takahiro Ishizaki ◽  
Tomohiro Miyashita ◽  
Momo Inamura ◽  
Yuma Nagashima ◽  
Ai Serizawa

Mg alloys are expected to be used in fields of the transportation industry because of their lightweight property, however, they show low corrosion resistance. To improve the corrosion resistance, preparation of the protective film on Mg alloys is essential. In this study, composite hydroxide films were prepared on three types of Mg alloys with different aluminum contents—that is, AZ31, AZ61, and AZ91D—by steam coating to investigate the relationship between the Mg-Al layered double hydroxide (LDH) content in the film and the Al content in the Mg alloys. Scanning electron microscopy (SEM) observation demonstrated that films were formed densely on all Mg alloy surfaces. X-ray diffraction (XRD) analyses revealed that all films prepared on AZ61 and AZ91D were composed of Mg(OH)2, AlOOH, and Mg-Al LDH, while the film containing Mg(OH)2 and Mg-Al LDH were formed only on AZ31. The Mg-Al LDH content in the film prepared on AZ61 was relatively higher than those prepared on AZ31 and AZ91D. The content of AlOOH in the film increased with an increase in the Al content in the Mg alloys. The film thickness changed depending on the treatment time and type of Mg alloy. Polarization curve measurements in 5 mass% NaCl solution demonstrated that the film prepared on the AZ61 showed complete passive behavior within the potential range of −1.0 to −0.64 V. In addition, immersion tests in 5 mass% NaCl aqueous solution for 480 h demonstrated that the film on the AZ61 had superior durability against 5 mass% NaCl aqueous solution. These results indicated that the film on the AZ61 had the most superior corrosion resistance among all samples. The results obtained in this study suggest that the LDH content in the film could be related to the corrosion resistance of the film.


2020 ◽  
Author(s):  
Tianfang Wang ◽  
Guoying Ni ◽  
Tsuyoshi Furushima ◽  
Hui Diao ◽  
Pingping Zhang ◽  
...  

Abstract Magnesium (Mg) has mechanical properties similar to human bones and Mg alloy is considered ideal medical implant material. However, the high velocity of degradation inside the human inner environment severely hampers the usage of Mg alloys. In this study, caerin peptide 1.9 (F3) and a modified sequence of caerin 1.1 (F1) with anti-bacterial activity, were covalently immobilised on the surface of Mg alloys by plasma chemical click reaction. The in vitro antibacterial activity and corrosion resistance of these caerin peptide-immobilised Mg alloys were investigated in Dulbecco's Modified Eagle Medium (DMEM) solution. Un-immobilised Mg alloy sample, blank drug-sensitive tablet (BASD) and a commonly used antibiotics Tazocin were used for comparison. Results showed that peptide immobilised Mg samples showed significant improved corrosion resistance and prolonged antibacterial effect compared to non-immobilised Mg alloy and free caerin peptides. Furthermore, annealing or extruding treatment of Mg alloys improved the behaviours of corrosion resistance and antibacterial property. These results indicate that coating Mg alloy with caerin peptides improves the corrosion resistance in vitro and increases the alloy’s antibacterial ability. The mechanism underlying the prolonged antibacterial effect for annealed Mg alloys immobilised with the peptides (especially F3) remains unclear, which worth further experimental and theoretical investigation.


Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 765 ◽  
Author(s):  
Dan Song ◽  
Jinghua Jiang ◽  
Xiaonan Guan ◽  
Yanxin Qiao ◽  
Xuebin Li ◽  
...  

Surface nano-crystallization (SNC) of a conform-extruded Cu-0.4 wt.% Mg alloy was successfully conducted by high-speed rotating wire-brushing to obtain the deformed zone with dislocation cells and nanocrystallines. SNC promotes the anodic dissolution and corrosion rate of the Cu-Mg alloy in the initial stage of immersion corrosion in 0.1 M NaCl solution. The weakened corrosion resistance is mainly attributed to the higher corrosion activity of SNC-treated alloy. With extending the immersion time, the SNC-treated alloy slows the corrosion rate dramatically and exhibits uniform dissolution of the surface. The formation of the dense corrosion products leads to the improvement of overall corrosion performance. It indicates that the SNC-treated Cu-Mg alloy can function reliably for a longer duration in a corrosive environment.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3651 ◽  
Author(s):  
Yanan Cui ◽  
Yonghai Wang ◽  
Zhongyu Cui ◽  
Wenlong Qi ◽  
Jidong Wang ◽  
...  

The influence of rare earth element (RE) Y on the microstructure and corrosion behavior of extruded AZ91 Mg alloy was surveyed via morphology characterization and corrosion performance measurements. The results indicate the corrosion resistance of the transversal section of AZ91 Mg alloy containing Y was improved compared with AZ91 Mg alloy without Y. The corrosion resistance of the longitudinal section of AZ91 Mg alloy with Y was lower than that of AZ91 Mg alloy without Y. The change of corrosion resistance can be attributed to the dispersion and volume fraction of the second phase, the effect of cathodic reduction rate, and the refined second phase.


2014 ◽  
Vol 887-888 ◽  
pp. 1076-1079
Author(s):  
Qiong Jiang ◽  
Qiang Miao ◽  
Wen Ping Liang ◽  
Bei Lei Ren ◽  
Yi Xu ◽  
...  

New waterborne Al-Zn-Si-RE coatings with improved corrosion resistance were introduced in this study. The corrosion resistance of Al-Zn-Si-RE coatings was evaluated by electrochemical measurements and salt spray test. Evolution of microstructure and phase composition at different exposure time in salt spray test was investigated by scanning electron microscopy and X-ray diffraction technique. The results indicate that Al-Zn-Si-RE coatings provide effective sacrificial protection to the steel substrate but exhibit lower corrosion rate and higher corrosion resistance compared to zinc aluminum coatings. The dense continuous corrosion layer formed on Al-Zn-Si-RE coating acts as a barrier layer, limiting the transport of aggressive species towards the coating-substrate interface and the corrosion rate of the coating; Zinc aluminum hydroxy carbonates are the dominant components in the corrosion layer of Al-Zn-Si-RE coatings.


2021 ◽  
Vol 61 (3) ◽  
pp. 456-464
Author(s):  
Jadamuni Senthilkumar ◽  
Pavan S. M. Kumar ◽  
Manickam Balasubramanian

The aluminium-based hybrid metal matrix composites have noteworthy applications in sub-sea installations, structures of deep-sea crawlers, submarine parts, engine cylinders, drum brakes etc., as they possess high strength, corrosion resistance, chemical, and dimensional stability. In this investigation, the pitting corrosion behaviour of friction welded and post-weld heat-treated AA6061/SiC/graphite hybrid composites were analysed. The corrosion rates of AW (as welded), ST (Solution treated), STA (Solution treated and Aged), and AA (Artificially Aged) weld joints were experimentally determined. The corrosion behaviour has been discussed in light of microstructure. The experimental results revealed that the STA joints exhibited better corrosion resistance characteristics as compared to AW, AA, and ST joints. The corrosion rate was high for AW joints, followed by AA and ST joints, respectively. Taking into account the corrosion rates of AW and STA joints, the STA joints have a corrosion rate 34.6% lesser than that of AW joints. A comparison of AA and ST with STA joints reveals that the rate of corrosion for STA joints was 31.1% lesser than that of AA joints and 28.8% lesser than that of ST joints. A lower corrosion rate was observed for STA joints as compared to AA, AW, and ST joints.


2013 ◽  
Vol 278-280 ◽  
pp. 422-425 ◽  
Author(s):  
Ya Fang Tian ◽  
Xian Hui Li ◽  
Zheng Hong Ao ◽  
Yu Jun Xue

The Ni- ZrO2 nanocomposite coatings were prepared by pulse electrodeposition with rotating cathode in an ultrasonic field, and the corrosion resistance of the coatings were studied in 5% H2SO4. The surface morphologies of composite coatings after corrosion were analyzed by scanning electron microscope (SEM). And corrosion rate was tested using an electronic balance. The results shows that, compared with pure Ni coating, pulse current composite coating and pulse current composite coating with ultrasound, the Ni-ZrO2 nanocomposite coating prepared by pulse electrodeposition with rotating cathode in an ultrasonic field has more uniform micro-structure, more compacted grain and lower corrosion rate. Peculiarly, it exhibits excellent corrosion resistance.


Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 70
Author(s):  
Aneta Kania ◽  
Magdalena M. Szindler ◽  
Marek Szindler

Magnesium alloys have been investigated as temporary biomaterials for orthopedic applications. Despite their high osseointegration and mechanical (bone-like) properties, Mg alloys quickly degrade in simulated physiological media. Surface coatings can be deposited onto Mg alloys to slow the corrosion rate of these biomaterials in chloride-rich environments. TiO2 films show high potential for improving the corrosion resistance of magnesium alloys. This article presents the structural observations and corrosion behavior of TiO2 thin films deposited onto a MgCa2Zn1Gd3 alloy using atomic layer deposition (ALD). Surface morphologies were observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM), and Raman analysis of the deposited TiO2 films was also carried out. The corrosion behavior of the uncoated alloy and the alloy coated with TiO2 was measured in Ringer’s solution at 37 °C using electrochemical and immersion tests. The microscopic observations of the TiO2 thin films with a thickness of about 52.5 and 70 nm showed that the surface morphology was homogeneous without visible defects on the TiO2 surface. The electrochemical and immersion test results showed that the thin films decreased the corrosion rate of the studied Mg-based alloy, and the corrosion resistance was higher in the thicker TiO2 film.


2020 ◽  
Vol 27 ◽  
pp. 50-60
Author(s):  
Guy Ben Hamu ◽  
Polina Metalnikov

Magnesium (Mg) alloys constitute an attractive structural material for transportation industries, due to their low density and high strength/weight ratio. However, high susceptibility to corrosion of Mg alloys limits their use. Therefore, there is a growing interest for development of new Mg alloys with good mechanical properties and superior corrosion resistance. Production of wrought Mg alloys results in enhancement of mechanical properties, whereas addition of alloying elements may result in improved corrosion behavior. In this study we distinguish the role of aluminum, zinc, tin and calcium additions on the corrosion performance of new wrought Mg alloys. Overall, addition of alloying elements resulted in precipitation of second phase particles with cathodic behavior (relatively to Mg matrix). This enhanced the micro-galvanic effects and the corrosion resistance in short periods of immersion was deteriorated. However, in longer periods of immersion the passive characteristics of the oxide layer played a significant role in improving the alloys' corrosion resistance. The contribution of each element to the oxide layer will be discussed in detail. In general, the quantities of alloying element should be sufficient to stabilize the corrosion products layer; yet as low as possible, in order to reduce the micro-galvanic effects.


2011 ◽  
Vol 686 ◽  
pp. 319-324
Author(s):  
Hong Yan Xu ◽  
Sen Chang ◽  
Xing Zhang ◽  
Zhi Min Zhang

Aluminum (Al) coating was thermally sprayed on the surface of AZ80 magnesium (Mg) alloy. The Al-coating was deformed at 400°C with different deformation degrees of 15%, 30%, 45%, 60% and 80%. The corrosion properties of the AZ80 Mg alloys coated with Al-coatings were studied by potentiodynamic and galvanic tests in 3.5% NaCl solution; the adhesion strengths between Al-coatings and AZ80 substrate were also measured simultaneously by tensile test. The results showed that, Al-coating could decrease the corrosion rate of AZ80 Mg alloys, and the corrosion rate was related not only with the density of Al-coating but also with the adhesion strength of Al-coating. Before the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg alloys decreased with the increasing of bonding strength of Al-coating; after the formation of dense Al-coating, the corrosion rate of Al-coated AZ80 Mg was mainly determined by the structure of Al-coating. It was also revealed that with the increasing of deformation degree, the corrosion rate of the Al-coated AZ80 Mg alloys first decreased then increased, while the adhesion strength increased gradually. The corrosion rate of AZ80 Mg alloy coated with 60% deformed Al-coating was the lowest, which was only 19% of that of the AZ80 substrate.


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