Electrochemical Corrosion Studies of Thixomolded AZ91D Alloy in Sodium Chloride Solution

Nakatsugawa, Isao; Takayasu, Hidenori; Araki, Katsuyuki; Tsukeda, Tadayoshi

doi:10.4028/www.scientific.net/msf.419-422.845

Cited by 7 publications

(6 citation statements)

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“…at which Mg alloy depassivates and initiates localized corrosion. 27,31 For the Mg alloy analyzed in this study, the value seems to be located at approximately 0.09 M. It is apparent that C crit. also influences the galvanic corrosion behavior.…”

Section: D Profile-figuresmentioning

confidence: 64%

“…Polarization curves of AZX611 and A6N01.-Figure 2 shows the potentiodynamic polarization curves of the AZX611 and A6N01 samples in different C NaCl . For the anodic polarization curves an inflection point suggesting a pseudo passivation-depassivation phenomenon 27 was observed at C NaCl of 0.04 and 0.09 M. At higher C NaCl , this inflection point disappeared and the current increased monotonically with a low anodic Tafel slope, which is characteristic to Mg dissolution. 19 As a result, the anodic crossed with the cathodic polarization curves near the corrosion potential of AZX611.…”

Section: Resultsmentioning

confidence: 86%

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Effect of NaCl Concentration on the Galvanic Corrosion Behavior of a Magnesium AZX611/Aluminum A6N01 Alloy Joint

Nakatsugawa

Chino

2020

J. Electrochem. Soc.

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The time variation of galvanic corrosion that occurred in an AZX611 magnesium/A6N01 aluminum alloy in differently concentrated NaCl solutions was evaluated by galvanic potential/current measurements and the Scanning Vibrating Electrode Technique (SVET). The weight loss and surface profile of alloy samples after the test were measured to quantify the degree of galvanic corrosion. The galvanic current showed a maximum at the initial stage and then decreased with time. Higher concentrations of NaCl resulted in higher currents, and the decay proceeded at a slower rate. The weight loss measurement revealed that galvanic corrosion damaged not only AZX611 but also A6N01 due to the surface alkalization caused by the cathode reaction. SVET detected numerous local anodes on the AZX611 surface, which gradually disappeared and were replaced with passive areas. As the NaCl concentration increased, local anodes appeared at the joint, which agrees with the results of previous studies. For the A6N01 counterpart, the entire surface was corroded regardless of NaCl concentration. The analysis of the surface profile supported the SVET results. It was concluded that the galvanic corrosion of the AZX611/A6N01 joint was controlled by the depassivation behavior of the AZX611 anode, in which the NaCl concentration was critical.

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Section: D Profile-figuresmentioning

confidence: 64%

Section: Resultsmentioning

confidence: 86%

Effect of NaCl Concentration on the Galvanic Corrosion Behavior of a Magnesium AZX611/Aluminum A6N01 Alloy Joint

Nakatsugawa

Chino

2020

J. Electrochem. Soc.

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“…The magnesium alloy is currently the lightest metal structure material in industrial applications. Its density is only 1.74 g cm- 3 , witch is approximately 35% smaller compared to Al-based alloys and 65% smaller than that of Ti-based alloys. The magnesium alloy is also high in specific strength and specific stiffness and excellent in casting, cutting and electromagnetic shielding performance [1,2].…”

Section: Introductionmentioning

confidence: 90%

Electron Beam Surface Alloying of a Magnesium Alloy with Al

Yan

2008

KEM

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Magnesium alloy is an important engineering materials，but the wider application is restricted by poor corrosion and wear resistance. In the present study, an attempt was made to enhance corrosion resistance and microhardness of Mg alloy AZ91D by electron beam alloying. Flame spray method was used to prepare Al coating on the surface of AZ91D magnesium alloy, then remelted by high power electron beam. The microstructure and composition of the coating were analyzed in detail. Al-Mg diffusion was produced between the coating and the substrate to lead to the re-distribution of alloy elements in the melted layer. The coating was mainly composed of Al-Mg solid solution, Mg-Al intermetallic compounds and Mg-Al solid solution transition zone. Microhardness of the alloying layer was enhanced to 220 HV0.05 as compared to 70-80 HV0.05 of the substrate, due to the intermetallic phase formation, such as Mg2Al3 and Mg17Al12. These phases were good to improve anticorrosion property of AZ91D alloy．

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“…But certain problems such as the quality and working environment still exist in the die casting process and need to be improved. On the other hand, Thixomolding®, has been developed and used for mass production of magnesium alloy component parts in the last few years [1][2][3]. This is a process to inject magnesium alloy slurry into a die cavity and provides near net-shape products from solid feed stock chip.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, it is possible to mold magnesium alloy slurry in semi-solid state. This can result in a product with few defects and superior dimensional accuracy [2][3]. By optimizing the process parameters, thixomolded® magnesium alloys (AZ91D, AM60B, AM50A, and AS41B) showed better mechanical properties and corrosion resistance than die cast ones [4][5][6].…”

Section: Introductionmentioning

confidence: 99%