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Dilute Mg–Al–Mn–Ca–Gd alloy with extraordinary corrosion resistance (P H = 0.21 mm/year) comparable to that of high-purity Mg was prepared. The Gd addition promoted the second phase transformation from the Al–Mn phase to the Al 8 Mn 4 Gd and Al 2 Gd phases with decreased potential difference with Mg matrix, thus weakening the micro-galvanic corrosion. The homogeneous distribution of nano-sized second phases effectively inhibited localised corrosion, contributing to the integrity of surface film. Furthermore, Gd alloying promoted the formation of compact corrosion products mixed with Gd 2 O 3 and embedded with the nano-sized Al 2 Gd phase, resulting in a stable and protective surface film. [Display omitted] • Dilute Mg alloy with corrosion resistance comparable to high-purity Mg is prepared. • Gd promotes the transformation of Al-Mn phase to less noble Al 8 Mn 4 Gd and Al 2 Gd phase. • The uniform distribution of dense nano-sized phase inhibits localised corrosion. • The surface film containing Gd 2 O 3 and nano-sized Al 2 Gd is more protective to matrix. [ABSTRACT FROM AUTHOR]

The corrosion problem of Mg alloys remains a significant barrier to their technical applications. Particularly challenging is meeting specific functional requirements while enhancing corrosion resistance. Here, a novel metal organic composite coating (PDA-Cu) has been developed, exhibiting excellent corrosion resistance, strong bonding strength, and potent antibacterial properties. In 3.5 wt% NaCl solution, the corrosion rate of PDA-Cu alloy was significantly lower than that of bare Mg alloy, about 1/360; it had a strong inhibition rate (100%) and high binding strength (23.75 N). Importantly, the composite coating maintains consistency across various substrates and forms, proving its adaptability and expanding its potential applications. [Display omitted] • This study presents an "Old Cloth" donning "Armor" strategy to chemically reduce a Cu layer (armor) on the PDA (old cloth). • The PDA-Cu composite coating endows magnesium alloys with excellent corrosion resistance. • PDA-Cu can be successfully applied to diverse materials, including metals, inorganics, and organics of various shapes. • The critical load of PDA-Cu reaches as high as 23.75 N, significantly surpassing other antibacterial coatings. • The PDA-Cu composite coating exhibits robust antimicrobial performance. [ABSTRACT FROM AUTHOR]

PEO coatings, aside from their reasonable corrosion protection, also feature a porous microstructure that can serve as a repository for corrosion inhibitors. This study presents and investigates the high corrosion inhibition effect of sodium salt of decylphosphonate (DP) when incorporated into PEO coating on a magnesium substrate. The interaction of DP with both bare and PEO-coated magnesium substrates was studied to understand its corrosion inhibition mechanism. Additionally, a strategy to enhance the active anti-corrosion ability of the DP-containing system was suggested and examined. The findings provide new insights into the potential of surfactants as corrosion inhibitors for magnesium alloys. • DP can significantly reduce the corrosion of both Mg and PEO coating. • interaction of DP with both bare and PEO coating is investigated in detail. • degradation of both Mg substrate and PEO promotes the inhibition effect of DP. • an approach to enhance active inhibition properties of DP was proposed and examined. [ABSTRACT FROM AUTHOR]

Research about magnesium corrosion inhibitors focuses on their influence on corrosion rate, but little attention is paid to whether the service reliability of alloys is improved by the inhibitors. In this work, the effects of selected corrosion inhibitors on the corrosion rate and localized corrosion behavior of magnesium alloy were compared. It is found that some corrosion inhibitors fail to inhibit the localized corrosion of magnesium, resulting in the inability to effectively maintain the mechanical bearing capacity of the corroded magnesium alloy. This study is of great significance for establishing reasonable screening and evaluation criteria for magnesium alloy corrosion inhibitors. • SDBS and PDCA effectively slows down the corrosion rate of Mg alloy but cannot completely inhibit localized corrosion. • SA slightly accelerates Mg corrosion but delays the decline of mechanical properties of alloy. • PCCys significantly slows down the corrosion rate and inhibit the localized corrosion of Mg alloy. • Inhibition efficiency of corrosion inhibitor has no direct link to its effect on the mechanical bearing capacity of Mg alloy. [ABSTRACT FROM AUTHOR]

Abstract The corrosion behaviour of magnesium and a WE43 magnesium alloy in a 1 M NaCl aqueous solution was studied by potentiodynamic polarisation and advanced acoustic emission (AE) analyses. The AE parameters suitable for monitoring the corrosion in magnesium were shown to be the AE counts, rise time, and duration. Moreover, the mechanisms of corrosion in these materials, i.e., ion exchange, rupture of the protective film, and pitting corrosion were identified and their evolution was followed by the novel Adaptive sequential k-means clustering technique. The presented methods can also be suitable for monitoring different materials and for industrial applications. [ABSTRACT FROM AUTHOR]

The effect of Sr addition on corrosion behaviour of AZ31 was investigated. The corrosion properties were characterized by immersion, electrochemical, scanning Kelvin probe microscopy and microstructural experiments. With increasing Sr concentration, the Vf of Al-Sr precipitates increases. Furthermore, SKPFM results show that Al-Sr and Al-Mn precipitates are cathodic compared to the base Mg matrix. Consequently, more micro-galvanic cells are formed by more precipitates resulting in severe corrosion attack. Corrosion starts at regions close to the precipitates and proceeds through the inter-precipitate region. Nyquist plots indicate that the stability of hydroxide/oxide protective film decreased with increasing Sr concentration. [ABSTRACT FROM AUTHOR]

We report that the corrosion resistance of Mg–8Sn–1Zn–1Al alloy is significantly improved by the application of a low-temperature indirect extrusion process utilizing artificial cooling. It was found that the corrosion rates, measured by immersion tests in 0.6 M NaCl solution at 25 °C, are 27.5 and 246.7 mm y −1 for the alloys extruded with and without artificial cooling, respectively. The remarkably improved corrosion resistance is mainly attributed to the reduced nobility of cathodic Al 5 Fe 2 particles, which results in retarded microgalvanic corrosion in the corrosive condition. Metallurgical factors affecting the electrochemical nobility of Al 5 Fe 2 particles are discussed. [ABSTRACT FROM AUTHOR]

This work reports on the validation studies of early corrosion sensing poly ether imide (PEI) coatings with incorporated pH-sensing phenolphthalein loaded silica nano-sized capsules (SiNCs-PhPh) on AZ31 magnesium alloys. Immersion and drop tests validated the high sensing accuracy and PhPh color-signaling reproducibility of the coatings upon onset of corrosion. This behavior is correlated to the homogeneous dispersion of SiNC particle agglomerates confirmed by 3D Raman mapping and SEM analysis. Complementary differential video imaging technique (DVIT) assisted by electrochemical impedance spectroscopy (EIS) investigations provided clues for a good correlation between the kinetics of color signaling and the corrosion activity. Mechanistic insights into the pH-sensing/color-signaling functionality in PEI coatings are suggested. [ABSTRACT FROM AUTHOR]

A hybrid PEO-epoxy coating was developed for magnesium. A highly-efficient corrosion inhibitor (3-methysalicylate) was impregnated into the anodized layer, which was sealed by an epoxy layer through dip-coating process. Influence of dip-coating parameters on coating properties was investigated. The corrosion performance was evaluated through general and localized electrochemical techniques. As a result, the epoxy layers registered superior resistance, whereas the anodized layer suppressed corrosion expansion. Longer immersion and triple-dipping favored the production of better sealed epoxy layer. The active protection mechanism was achieved by suppression the re-deposition of detrimental impurity and/or adsorption upon the exposed surface from incorporated inhibitor. [ABSTRACT FROM AUTHOR]

Friction stir processing (FSP) is applied to modify the surface microstructure of cast AZ91 magnesium alloy. The electrochemical and hydrogen evolution measurements reveal that the corrosion rate of processed alloy in 3.5 wt% NaCl solution is significantly decreased. This is mainly attributed to the alteration of corrosion process induced by modification on the morphology and distribution of β-Mg 17 Al 12 phase via FSP. It is originally reported that the formation of a compact and continuous β phase layer on the FSPed surface owing to the segregation of fine β phase effectively enhances the stability and passivity of corrosion product film. [ABSTRACT FROM AUTHOR]

The present paper reports a quasi-in-situ STEM-EDS approach for studying the role of Ag in the corrosion behaviour of Mg-Gd-Zr alloys. Following corrosion, the segregation of O at the interface of the α-Mg matrix and the β phase was observed. Furthermore, Ag-rich particles and the re-deposition of Ag were also observed on the nanoscale. Based on quasi-in-situ STEM-EDS observations herein, the partitioning of Ag into the β phase leads to enhanced localised corrosion, whilst the subsequent formation of Ag-rich particles during the corrosion process leads to enhanced rate of corrosion propagation, with accompanying oxy-hydroxide formation observed upon the Mg-Gd-Ag-Zr. [ABSTRACT FROM AUTHOR]

Actively propagating localized corrosion fronts on pure Mg, Mg-Zn-Ca-Mn, and Mg-Y alloys in NaCl aqueous solutions were investigated by site-specific characterization techniques. Regardless of alloy microstructure and polarization conditions, rising streams of hydrogen bubbles were observed predominantly at the propagating corrosion fronts. Localized corrosion propagated inside the alloys, underneath a surface corrosion film, and exhibited a finger-like morphology at the corrosion region/alloy interface. Hydrogen evolution was found to be related to the formation of corrosion products and followed local anodic dissolution of Mg. Localized corrosion morphology strongly varied with the underlying Mg alloy microstructure and chemistry. [ABSTRACT FROM AUTHOR]

Duplex Ni coatings consisting of Ni–P deposits as primer layer and Ni–Sn–P deposits as outer layer were prepared on Mg alloy. These coatings exhibit uniform surface and improved corrosion resistance after adding trace stannous (II) chloride (SnCl 2 ) into the outer layer plating bath. X-ray photoelectron spectroscopy proved the non-existence of Sn in the coating. The coating surface was characterized by scanning electron microscopy and atomic force microscopy. X-ray diffractometer patterns show that SnCl 2 is favourable for amorphisation of the coating. The corrosion protection of the coating was confirmed by potentiodynamic polarisation and electrochemical impedance spectroscopy measurement. [ABSTRACT FROM AUTHOR]

The effect of increasing the Al concentration to a value between 0.5 and 0.8 wt.% within the 10-μm thick surface layer of a commercial AZ31 alloy sheet manufactured by twin-cast rolling method on its corrosion behaviour was investigated. In long term exposure, both the uniformity of the double layered Mg-Al hydroxide (LDH) formed in the inner layer of the corrosion product on the aluminium-rich surface AZ31 specimen and the precipitation of a significant amount of aluminium hydroxide contributed to enhancing the corrosion resistance significantly. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was added into the electrolyte during the preparation of the plasma electrolytic oxidation (PEO) coating on AZ31 magnesium alloy. The effects of the GO additive on the microstructure, phase composition, and corrosion resistance of the PEO coating were studied. The results demonstrated that GO successfully incorporated into the PEO coating and it was partially reduced to rGO during the PEO process. As a result, the number of micropores on the PEO coating was significantly decreased. Moreover, the electrochemical test revealed that the corrosion resistance of the PEO coating was markedly improved upon the incorporation of 2 g/L GO. [ABSTRACT FROM AUTHOR]

In our previous work, a novel robustness mineralized layer was prepared on surface of AZ80–0.38Nd (wt%) alloy, which mainly consisted of rod-like structure MgCO 3 •3 H 2 O and flake structure 4MgCO 3 •Mg(OH) 2 •4 H 2 O. The mineralized layer exhibited outstanding robustness structure. While its corrosion protection for magnesium alloy has not been explored. In this paper, the corrosion behavior and protective performance of the robustness mineralized layer were investigated via hydrogen evolution and electrochemical measurements, systematically. The results show that the mineralized layer exhibited excellent anti-corrosion property in the NaCl solution compared with the oxide layer, due to the outstanding impermeability. And the mineralized layer presented better corrosion passivation and micro-galvanic corrosion inhibition effects due to the characteristics of slight defects and good adhesion to matrix. Besides, the mineralized layer could launch CO 3 2− during degradation of corrosion, which slowed down the penetration of Cl− across the layer and inhibited the attack of Cl− on magnesium substrate. The fabrication of robustness mineralized layer on magnesium alloys surface provides a novel effective strategy for improving the corrosion resistance of magnesium alloys. • The mineralized layer with robustness structure and slight defect shows excellent anti-corrosion property in NaCl solution. • The mineralized layer presents micro-galvanic corrosion inhibition characteristic. • The mineralized layer promotes corrosion of magnesium alloy to develop slowly and uniformly. • The mineralized layer can launch CO 3 2− during degradation, which slows down the attack of Cl− on magnesium substrate. [ABSTRACT FROM AUTHOR]

The as-cast, homogenized, and peak-aged AZ63 alloys are investigated via microstructure observation, EDS analysis, hydrogen evolution, and electrochemical tests. The results suggest that the heat treatments exert an influence on the corrosion behavior of AZ63 alloy via the microstructure transformation. The corrosion of homogenized alloy is retarded by protective oxide layer at first, but achieves highest corrosion rate among the three alloys owing to the less protective products film. The micro-galvanic couples endow the as-cast and peak-aged alloys high dissolution activity, but the adhesive products alleviate the corrosion. Two models are proposed to interpret the dissolution mechanism for these alloys. [ABSTRACT FROM AUTHOR]

This paper reviews and discusses the possibility of the production of a passive magnesium (Mg) alloy through metallurgical approaches, such as purification, alloying, heat-treatment, mechanical processing and non-equilibrium sputter deposition. High-purity Mg and all existing Mg alloys produced by traditional methods are found to be active in a chloride containing solution. Passivity in a Mg alloy might be produced through a non-equilibrium technique with a sufficiently-high concentration of a strong passivating element supersaturated in the matrix phase. This paper clarifies important concepts regarding the passivity of Mg alloys, and suggests possible approaches to develop a passive, corrosion-resistant Mg alloy. [ABSTRACT FROM AUTHOR]

Perfluorinated polysiloxane [-(SiR 1 R 2 -O) n -, where R 1 is -OH and R 2 is -CH 2 ) 2 -(CF 2 ) 5 -CF 3 ], was synthesized from 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) and hybridized with graphene oxide (GO). The composite (PPFS/GO) was applied to AZ31 Mg alloy for corrosion protection in NaCl. Efficient inhibition by PPFS/GO was realized due to a synergistic effect via the remnant hydrophobic-properties of PFOTES and the high surface area of GO. The polymeric nature of PPFS also contributed to the strong adhesion between the coating layer and AZ31, making this work different to most previous reports where the Mg surface was pretreated before coating. [ABSTRACT FROM AUTHOR]

Mg alloys are promising candidates for biodegradable materials. To control their dissolution rate, the orientation-dependent corrosion behaviour of pure-Mg single crystals was examined. The corrosion rates increased in the order ( 0001 ) < ( 11 2 ¯ 0 ) < ( 10 1 ¯ 0 ) < ( 11 2 ¯ 3 ) < ( 10 1 ¯ 2 ) . We found the anodic reaction governs the orientation-dependent corrosion behaviour. The charge-transfer and film resistances were strongly orientation-dependent. Effects of Al or Cu-addition to the orientation-dependent corrosion behaviour were also examined as model materials. Al-addition promoted passivation in anodic polarization, while Cu-addition activated the cathodic reaction. However, neither Al nor Cu influenced the order of orientation-dependent corrosion behaviour. Such orientation-dependence may originate from the variation in surface atomic-packing density. [ABSTRACT FROM AUTHOR]

The way of self-healing coating formation at the surface of magnesium alloys on the base of plasma electrolytic oxidation method (PEO) has been suggested. Scanning Vibrating Electrode Technique (SVET) and Scanning Ion-Selective Electrode Technique (SIET) were used for determining the kinetics and mechanism of the self-healing process. The treatment of the PEO-layer by the solution containing 8-hydroxyquinoline enables one to decrease the current density of the composite coating in 30 times (3.2 μA cm −2 ) in the corrosion-active environment in comparison with the base PEO-coating (100 μA cm −2 ) and avert the intensive destruction of the material. [ABSTRACT FROM AUTHOR]

The method of the inhibitor-containing coatings formation with self-healing properties on the surface of magnesium alloys has been developed. The obtained experimental results indicate that the protective properties of the samples with inhibitor-containing coating were increased in comparison with the samples without coating and the base coating obtained by plasma electrolytic oxidation method (PEO). Electrochemical parameters of the porous and poreless layers on the surface of the samples have been calculated before and after polarization due to experimental impedance data modeling by means of the equivalent electrical circuits. [ABSTRACT FROM AUTHOR]

In the present study the reactive surface of Mg alloy was coated with the nontoxic biocompatible polypyrrole (PPy) film synthesized by electrochemical oxidation from an aqueous salicylate solution. Salicylate ions prevent Mg dissolution and act as an electron transfer mediator during the PPy film nucleation, formation and growth on the alloy surface. Kinetics of the pyrrole polymerization as well as corrosion resistance of the PPy coated Mg alloy in the Hanks’ solution were investigated using dc electrochemical methods and electrochemical impedance spectroscopy (EIS). Characterization of the surface film was performed by optical and Fourier transform infrared spectroscopy (FTIR). [ABSTRACT FROM AUTHOR]

A novel mixture, comprising sodium fluoride (NaF) and 3-amino-1,2,4-triazole-5-thiol (ATT), was reported as an effective hybrid corrosion inhibitor for magnesium alloy in pH neutral NaCl solution. The highest efficiency (95.8%) was achieved when 50 mM NaF and 5 mM ATT were mixed. Both experimental and theoretical approaches were employed for addressing the synergism. The synergism was proposed as the formation of a double-layered inhibitors film, in which the lower layer is a uniform fluoride-enriched precipitate layer and the upper one is a hydrophobic adsorption layer. These two layers were mutually strengthened to produce an excellent inhibition effect as a whole. [Display omitted] • A synergistic inhibition effect was discovered between 3-amino-1,2,4-triazole-5-thiol (ATT) and NaF for AM50 alloy corrosion. • Optimum mixing concentration ratio was determined as the 50 mM NaF with 5 mM ATT. • Proposed a novel adsorption and precipitation co-enhanced corrosion inhibition synergism. [ABSTRACT FROM AUTHOR]

Ten kinds of magnesium alloys with various chemical compositions and/or microstructures were exposed to actual atmospheric environments for three years, and the influences of chemical compositions and microstructures on atmospheric corrosion behavior of magnesium alloys were investigated. The results showed that the atmospheric corrosion resistance of magnesium alloys generally increased with the Al content in the alloys, but intermetallic phases had a considerable influence on the corrosion resistance. Grain refinement improved the corrosion resistance of magnesium alloys. It was also found that atmospheric corrosion rate increased with exposure time, and this phenomenon was explained in the present work. [ABSTRACT FROM AUTHOR]

This study evaluates the corrosion inhibitive abilities of ammonium phosphate dibasic, 8-hydroxyquinoline, calcium fluoride, sodium fluoride, sodium dodecylbenzenesulfonate and zinc nitrate with respect to the protection of the magnesium ZK30 alloy to NaCl solution. A set of characterization assays addressing morphology, composition and structural aspects of the exposed alloys were conducted, along with electrochemical evaluations. The results reveal that upon corrosion new compounds are formed onto the exposed areas of the treated alloys. The conducted experiments shed light on the corrosion mechanisms for Mg ZK30, paving the way for future developments in this area. [ABSTRACT FROM AUTHOR]

The influence of Nd on the atmospheric corrosion performance of AZ91 alloy was evaluated as per PV1210 standard. Additionally, immersion and electrochemical measurements were carried out. The beneficial effect of Nd is associated with: (i) suppressed galvanic corrosion between α-Mg and secondary phases, (ii) refined β-phase morphology and (iii) increased proportion of carbonates in the outer surface layer. In case of atmospheric corrosion, the role of β-phase is the least important factor out of the three. The optimum Nd content is 0.5 wt.%. Further additions do not improve significantly the corrosion performance. [ABSTRACT FROM AUTHOR]

A polydopamine (PDA) layer was sandwiched between a TiO 2 coating and Mg substrate to enhance the corrosion protection. The PDA layer was covalently immobilized on Mg, and the TiO 2 was coated by liquid phase deposition subsequently on it. The hybrid TiO 2 /PDA coated Mg exhibited significantly smaller free corrosion current density as well as a remarkably lower degradation rate in vitro (up to 21 days) in phosphate buffered saline compared to direct TiO 2 coated and untreated Mg. The efficacy is ascribed to the organic PDA layer which suppresses the electric pathway of galvanic corrosion cell and therefore corrosion rate of magnesium. [ABSTRACT FROM AUTHOR]

Microstructure, composition and the corrosion resistance of Mg–Ca alloys were analysed using SEM, EDS, XPS, EPMA, XRD, electrochemical and immersion tests. The results revealed that Ca played a dual role, decreasing the corrosion rate due to the refinement of grain size and accelerating corrosion due to the formation of the Mg 2 Ca phase. The Mg 2 Ca particles coexisted with Fe and Si led to pitting corrosion. The Mg–0.79Ca alloy had the highest hardness, ultimate tensile/yielding strength and corrosion resistance in comparison with the Mg–0.54Ca and Mg–1.35Ca alloys, representing the promising candidate for degradable biomaterials. [ABSTRACT FROM AUTHOR]

The stress corrosion cracking (SCC) behaviour of solution heat-treated as-cast Mg0.1Zr, Mg1Mn, Mg0.1Sr, Mg0.3Si, Mg5Sn, Mg5Zn and Mg0.3Ca in distilled water (DW) was studied using the linearly increasing stress test (LIST). SCC susceptibility was related to the stress rate for all the Mg–X alloys except for Mg0.1Sr. At ∼7.0 × 10 −4 MPa s −1 , Mg0.3Si and Mg5Sn were immune to SCC; Mg0.1Zr, Mg1Mn and Mg0.1Sr suffered medium SCC; Mg5Zn and Mg0.3Ca suffered relatively more serious SCC. At ∼7.0 × 10 −5 MPa s −1 , Mg5Zn and Mg0.3Ca suffered the most serious transgranular SCC, whilst the other Mg–X alloys suffered medium SCC. [ABSTRACT FROM AUTHOR]

This investigation aims at providing deeper understanding of the interactive influence of the alloying elements calcium and zinc on biodegradable magnesium. Through the low-concentration variation of both alloying elements, the formation and distribution of microstructural phases and the in-vitro degradation behavior were investigated to gain mechanistic insights. Mg 2 Ca dissolves preferentially to α-Mg within Mg–Ca alloys. Mg 6 Ca 2 Zn 3 temporarily blocks local corrosion but is ultimately undermined due to its discontinuity. More ternary phases obtained by higher alloying contents of Zn and Ca increase the corrosion rate. At a Zn/Ca (atomic) of 1.84, a Zn-enrichment of α-Mg decreases potential differences between the phases. [ABSTRACT FROM AUTHOR]

The corrosion of an AM50 Mg alloy was studied in ethylene glycol using electrochemical and electron microscopy techniques. Switching from H 2 O to ethylene glycol, it was shown that the corrosion of the AM50 alloy was significantly suppressed thereby slowing H 2 evolution. The corrosion of the AM50 alloy was mapped using scanning electrochemical microscopy in the feedback mode. Ferrocenemethanol can be used to expose the reactive anodic areas on the Mg alloy. These studies confirmed that studies in ethylene glycol can be used to elucidate reaction features obscured by rapid corrosion in H 2 O without significantly altering the mechanism and damage morphology. [ABSTRACT FROM AUTHOR]

The corrosion rates of High Density Die Cast MRI 201S and three other magnesium alloys in 3% NaCl were measured. The side surfaces of some specimens were insulated by a polymer, while the other specimens had all the surfaces open to the corrosive media. No difference between the two types of specimens for was observed for AZ91D, MRI 153M and MRI 202S alloys, while for MRI 201S alloy the corrosion of the samples of the 1st type was significantly slower than of the 2nd type. For all the alloys studied, the coarser the grains the higher the corrosion rate. [ABSTRACT FROM AUTHOR]

Necessity for developing alternatives to chromate conversion coatings has increased in the last decade. A chromate-free conversion coating treatment, mainly in permanganate solution, was developed in this study for AZ31 magnesium alloys. The coating formed after 90 s of immersion consisted of a continuous nearly crack-free layer with an average thickness of 230 nm. The results of the electrochemical measurements and the salt spray tests demonstrated that the corrosion resistance of the AZ31 alloy was markedly improved by the permanganate conversion treatment. Moreover, this thin permanganate conversion coating had sufficient electrical conductivity, ensuring the magnetic shielding properties of the AZ31. [ABSTRACT FROM AUTHOR]

Highlights: [•] AZ80E and pure Mg exhibit self-passivation with time in phosphate buffer saline. [•] Hydrogen gas evolution on AZ80E alloy is found to be more facile than on pure Mg. [•] Corrosion layer resistance at any immersion time is higher for the alloy than Mg. [•] Corrosion parameters confirm the more passive behaviour of AZ80E relative to Mg. [•] Anodic oxidation at 1.0V(SCE) modifies AZ80E surface and increase its durability. [ABSTRACT FROM AUTHOR]

Highlights: [•] The presence of anions led to the formation of a corrosion product film. [•] The presence of anions decreased open circuit potentials and changed corrosion rates. [•] A model for the formation mechanism of magnesium carbonate film is proposed. [•] The pH change with time cannot reflect the corrosion rates of Mg alloys. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cells accelerate magnesium alloy corrosion rate. [•] Proteins slow down magnesium alloy corrosion rate. [•] Surface corrosion layer composition is studied. [•] Mechanisms how proteins and cells affect Mg alloy corrosion are proposed. [Copyright &y& Elsevier]

Highlights: [•] The number of through-pores in the coating determines the anodized Mg corrosivity. [•] The Mg dissolution in the through-pores is a time dependent multi-reaction process. [•] A more stable substrate alloy has a lower Mg dissolution rate in the through-pores. [Copyright &y& Elsevier]

Highlights: [•] Usefulness of positron beam measurement for characterization of corrosion layer. [•] The calcium carbonate was deposited on the surface of both HPDC and SVDC alloys. [•] Larger volume fraction of eutectic phase in SVDC alloy than HPDC alloy. [•] Higher corrosion resistance of SVDC alloy than HPDC alloy. [Copyright &y& Elsevier]

Highlights: [•] A homogenisation pre-treatment for electroplating Ni on AZ91D was studied. [•] The pretreatment effectively removed surface β-phase and promoted a surface suited to coating interlocking and deposition. [•] Adherent and corrosion-resistant Ni coating on AZ91D was achieved by electroplating. [•] The homogenisation pre-treatment can be extended to other coating technologies. [Copyright &y& Elsevier]

Highlights: [•] Atmospheric corrosion under humid air of zinc and zinc–magnesium pure phases were investigated. [•] The corrosion products were characterized in depth using X-ray photoelectron spectroscopy. [•] Migration of Mg atoms toward the surface was observed during ZnMg corrosion. [•] The chemical reactions were different for Zn and MgZn2 corrosion leading to different corrosion products. [Copyright &y& Elsevier]

Abstract: Kirkland et al. [1] state that their data was centred about n =2, where n is the charge per Mg ion delivered by the external current. However, values of n less than n =2 are calculated for each experimental condition from their data (Table 1). These calculated values are consistent with Mg corrosion involving the uni-positive Mg+ ion. However, their experimental details are unclear and contradictory, and consequently there is uncertainty concerning any conclusions made from the data. Kirkland et al. [1] dismiss much of the prior relevant literature. A summary is provided. [Copyright &y& Elsevier]

Highlights: [•] Effects of Zn2+ concentration and pH level on zinc phosphate conversion coatings are reported. [•] The coatings on AZ31 through zinc phosphating conversion coating solution are characterized as double layer structure. [•] The method for optimization of Zn2+ concentration and pH based on chemical equilibrium diagram is provided. [•] Zinc phosphating conversion coatings formed at [Zn2+]=0.068M and pH 3.07 showed the best corrosion resistance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Phytic acid was used to modify hydrotalcite films by adsorption or ion exchange way. [•] The corrosion resistance of hydrotalcite films is improved by modification using phytic acid. [•] Phytic acid modification provides a self-healing effect to hydrotalcite film. [ABSTRACT FROM AUTHOR]

Highlights: [•] Paeonol effectively inhibits the corrosion of AZ91D Mg alloy in 0.05wt.% NaCl solution. [•] The best inhibition is achieved with 50ppm paeonol addition. [•] Paeonol chelates with Mg and makes the surface film more compact and protective. [ABSTRACT FROM AUTHOR]

Abstract: Stress corrosion cracking of the magnesium alloy Elektron 21 (ASTM–EV31A) and AZ91E was studied using constant load test in 0.1M NaCl solution (saturated with Mg(OH)2), and slow strain rate test using glycerol, distilled water and Mg(OH)2 saturated, 0.01M and 0.1M NaCl solutions. Slow strain rate test indicated that EV31A was less susceptible to stress corrosion cracking than AZ91E. Under less intense loading of constant load, EV31A was found to be resistant to stress corrosion cracking. Fractography of EV31A specimens showed little evidence of hydrogen embrittlement. The superior resistance of EV31A is attributed to a more robust oxide/hydroxide layer. [Copyright &y& Elsevier]

Abstract: A fine-grained AZ31B alloy and a commonly hot-extruded AZ31B alloy with coarser grains were exposed to marine and urban environments for 1year, and the atmospheric corrosion behavior of the AZ31B alloys was investigated. The fine-grained AZ31B alloy displays slightly higher corrosion resistance than the commonly hot-extruded AZ31B, particularly in urban environment. Magnesium carbonate hydrate and hydromagnesite are principal corrosion products of the two AZ31B alloys in both marine and urban environments. Besides, it is found that Al–Mn intermetallic particles have little influence on the atmospheric corrosion of the AZ31B alloys. [Copyright &y& Elsevier]

Abstract: The corrosion resistance and semiconducting properties of the oxide film formed on the AZ91D alloy were evaluated. The alloy was tested in the as-cast condition and after a solution annealing treatment. Electrochemical impedance spectroscopy measurements and potentiodynamic polarization curves were obtained in a H3BO3 (0.05M)+Na2B4O7⋅10H2O (0.075M) solution with pH=9.2 at room temperature. The semiconducting properties of the oxide film were evaluated using Mott–Schottky plots. The corrosion resistance of the AZ91D was reduced after the solution treatment while the semiconducting properties of the passive films were little affected. [Copyright &y& Elsevier]

Abstract: The influence of the processing route and chemical composition in the corrosion behaviour of two Mg–Zn–Y–Mischmetal alloys has been evaluated in phosphate buffer saline solution. The corrosion resistance of the alloy processed by conventional techniques was substantially higher than that found for the same alloy processed from atomised powders. Fine homogeneous distribution of the second-phase particles promoted severe attack due to the enhanced number of galvanic microcells. A higher concentration of zinc and a lower content of rare earth additions improved the corrosion resistance of the alloys due to the lower volume fraction of second-phase particles. [Copyright &y& Elsevier]

Abstract: The work is an attempt to learn more about the role of several experimental variables in the corrosion of magnesium alloys in immersion tests carried out in 0.6M NaCl. The effect of as-received and polished surface conditions, geometrical characteristics of the exposed area and different aluminium contents in the magnesium based alloys is considered. Results indicated that polished surfaces and AZ61 surfaces tend to develop corrosion slower than the respective as-received and AZ31 surfaces; these tendencies can change by prolonging exposure time. Filiform and localised corrosion are influenced by the presence of cut surfaces and small exposed areas, respectively. [Copyright &y& Elsevier]