Research on Cerium Conversion Coating on ZM5 Magnesium Alloy

2014 ◽  
Vol 936 ◽  
pp. 1082-1085
Author(s):  
Rong Xia Zhu ◽  
Guo Mian Gao ◽  
Zheng Miao
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Formation Mechanism ◽  
Potentiodynamic Polarization ◽  
Conversion Coating ◽  
Experimental Results ◽  
Specimen Surface ◽  
Potentiodynamic Polarization Curves ◽  
Corrosion Behaviors ◽  
Cerium Salt

The conversion coating formed by immersion in a solution containing cerium salt on ZM5 magnesium alloy was studied and the corrosion resistance was evaluated as well. These micrographs of specimen surface were investigated by metallographic microscope. The corrosion behaviors of ZM5 magnesium alloy and conversion coating were assessed by means of potentiodynamic polarization curves and immersion tests. The experimental results indicated that a yellow-brown conversion coating was formed subsequently on the specimen surface. The results of electrochemical measurements and immersion tests revealed that the cerium conversion coating possessed better corrosion resistance than the substrate. In this study, cerium conversion coatings formed on ZM5 magnesium alloy were characterized and the formation mechanism was discussed.

EFFECT OF FRICTION STIR PROCESSING ON CORROSION BEHAVIOR OF CAST AZ91C MAGNESIUM ALLOY

2019 ◽  
Vol 26 (06) ◽  
pp. 1850213 ◽  
Author(s):  
BEHZAD HASSANI ◽  
RUDOLF VALLANT ◽  
FATHALLAH KARIMZADEH ◽  
MOHAMMAD HOSSEIN ENAYATI ◽  
SOHEIL SABOONI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Friction Stir Processing ◽  
Potentiodynamic Polarization ◽  
Passive Layer ◽  
Friction Stir ◽  
T6 Heat Treatment ◽  
Az91c Magnesium Alloy

The corrosion behavior of as-cast AZ91C magnesium alloy was studied by performing friction stir processing (FSP) and FSP followed by solution annealing and then aging. Phase analysis, microstructural characterization, potentiodynamic polarization test and immersion tests were carried out to relate the corrosion behavior to the samples microstructure. The microstructural observations revealed the breakage and dissolution of coarse dendritic microstructure as well as the coarse secondary [Formula: see text]-Mg[Formula: see text]Al[Formula: see text] phase which resulted in a homogenized and fine grained microstructure (15[Formula: see text][Formula: see text]m). T6 heat treatment resulted in an excessive growth and dispersion of the secondary phases in the microstructure of FSP zone. The potentiodynamic polarization and immersion tests proved a significant effect of both FSP and FSP followed by T6 on increasing the corrosion resistance of the cast AZ91C magnesium alloy. Improve in corrosion resistance after FSP was attributed to grain refinement and elimination of segregations and casting defects which makes more adhesive passive layer. Increase in volume fraction of precipitations after T6 heat treatment is determined to be the main factor which stabilizes the passive layer at different polarization values and is considered to be responsible for increasing the corrosion resistance.

Nano Al2O3/phosphate Composite Conversion Coating Formed on Magnesium Alloy for Enhancing Corrosion Resistance

2013 ◽  
Vol 160 (11) ◽  
pp. C553-C559 ◽  
Author(s):  
Ming Zhao ◽  
Jianguo Li ◽  
Guangping He ◽  
Honglan Xie ◽  
Yanan Fu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Conversion Coating

scholarly journals Improvement of bio-compatible AZ61 magnesium alloy corrosion resistance by fluoride conversion coating

2016 ◽  
Vol 60 (5) ◽  
pp. 132-138 ◽  
Author(s):  
J. Drábiková ◽  
F. Pastorek ◽  
S. Fintová ◽  
P. Doležal ◽  
J. Wasserbauer
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Simulated Body Fluid Solution ◽  
Conversion Coating ◽  
Az61 Magnesium Alloy ◽  
Wrought Magnesium Alloy ◽  
Consequent Effect ◽  
Materials Used ◽  
Short Time

Abstract Magnesium and its alloys are perspective bio-degradable materials used mainly due to their mechanical properties similar to those of mammal bones. Potential problems in utilization of magnesium alloys as bio-materials may relate to their rapid degradation which is associated with resorption problems and intensive hydrogen evolution. These problems can be eliminated by magnesium alloys surface treatment. Therefore, this work aims with analysis of the influence of fluoride conversion coating on corrosion characteristics of magnesium alloy. Unconventional technique by insertion of wrought magnesium alloy AZ61 into molten Na[BF4] salt at temperature of 450 °C at different treatment times was used for fluoride conversion coating preparation. The consequent effect of the coating on magnesium alloy corrosion was analyzed by means of linear polarization in simulated body fluid solution at 37 ± 2 °C. The obtained results prove that this method radically improve corrosion resistance of wrought AZ61magnesium alloy even in the case of short time of coating preparation.

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