Corrosion of Metals in Tropical Environments. Part 6. Aluminum and Magnesium

Southwell, C. R.; Hummer, C. W.; Alexander, A L

doi:10.21236/ad0609618

Cited by 20 publications

(24 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The corrosion rate of AZ91D, measured in µm/year, was after 12 months of exposure 4.2, 2.2 and 1.8 for marine, rural and urban exposure, respectively. Table 4 shows the corrosion rates of field-exposed AZ91D, and for the sake of comparison corrosion rates found in the literature are also included (38,39). The weight loss of the magnesium alloys exposed in the field were shown to be linear with time.…”

Section: Influence Of Exposure Parameters (Papers I and Iii)mentioning

confidence: 99%

Atmospheric Corrosion of Magnesium Alloys: Influence of Temperature, Relative Humidity, and Chloride Deposition

LeBozec¹,

Jönsson²,

Thierry³

2004

CORROSION

View full text Add to dashboard Cite

The low density and high specific strength of magnesium alloys have created a great deal of interest in the use of these alloys in the automotive and aerospace industries and in portable electronics. All of these industries deal with applications in which weight is extremely important. However, an obstacle to overcome when using magnesium alloys in engineering applications are their unsatisfactory corrosion properties. This thesis is devoted to the atmospheric corrosion of the two magnesium alloys AZ91D and AM50, in particular the ways the microstructure and exposure parameters of these alloys influence their corrosion behaviour. The work includes both laboratory and field studies. The results obtained show that the microstructure is of vital importance for the corrosion behaviour under atmospheric conditions. The microstructure of magnesium-aluminium alloys contains different intermetallic phases, e.g. Al 8 Mn 5 and β-Mg 17 Al 12. The local nobility of these intermetallic phases was measured on a submicron level in an atmospheric environment. It was shown that particles of the Al-Mn type exhibit the highest Volta potential among the microstructure constituents of the AZ91D magnesium alloy. Further, it was shown that the Volta potential was highly dependent on the aluminium content of the magnesiumaluminium phases in the surface layer. When thin electrolyte layers are present, CO 2 diffuses readily to the surface forming magnesium carbonate, hydromagnesite. The CO 2 lowers the pH in areas on the surface that are alkaline due to the cathodic reaction. This stabilises the aluminium-containing surface film, the result being increased corrosion protection of phases rich in aluminium. Both in the laboratory and under field conditions the corrosion attack was initiated in large α-phase grains, which is explained by the lower aluminium content in these grains. The thin electrolyte film, which is formed under atmospheric conditions, decreases the possibility of galvanic coupling of alloy constituents located at larger distances from each other. Thus the cathodic process is in most cases located in the eutectic α-/β phase close to the α-phases, instead of in intermetallic Al-Mn particles, even though the driving force for the initiation of the corrosion attack in Al-Mn particles should be high, due to their high nobility. .

show abstract

Section: Influence Of Exposure Parameters (Papers I and Iii)mentioning

confidence: 99%

Atmospheric Corrosion of Magnesium Alloys: Influence of Temperature, Relative Humidity, and Chloride Deposition

LeBozec¹,

Jönsson²,

Thierry³

2004

CORROSION

View full text Add to dashboard Cite

show abstract

“…Corrosion of magnesium (Mg) alloys during field exposure Some corrosion rates of Mg alloys at different field exposure sites given in the literature (25)(26)(27) are displayed in Table 7.2. The highest corrosion rate, 8.8 mm/year, is shown for the AM50 alloy exposed in marine environment for one year, i.e.…”

Section: 6mentioning

confidence: 99%

Atmospheric corrosion of magnesium (Mg) alloys

Jönsson¹,

Persson²,

Kimab³

2011

Corrosion of Magnesium Alloys

View full text Add to dashboard Cite

“…The use of aluminum in marine environments including atmospheric exposures, partial sea water immersion such as splash and tidal zones and total sea water immersion is well documented (5)(6)(7)(8)(9)(10)(11). For structural applications the corrosion resistant alloys maintain their integrity as measured by tensile properties for over 10 years in these environments.…”

Section: The Compatibility Of Aluminum Alloys With Sea Watermentioning

confidence: 99%

Concurrent studies of enhanced heat transfer and materials for ocean thermal exchangers. Progress report

Bonewitz¹

1976

View full text Add to dashboard Cite

Aluminum alloys 1100, 3003, 5052, and 6063 were examined for their compatibility with the proposed working fluids for Ocean Thermal Energy Conversion (OTEC), anhydrous ammonia, Freon 22 and propane, and mixtures of these with sea water. Such mixtures would occur if leaks develop in evaporator or condenser heat exchangers. These aluminum alloys are compatible with the anhydrous working fluids. In ammonia-sea water solutions only limited general corrosion is found in 0-30% ammonia, no corrosion in 30-90% ammonia, and "self limiting" pits in 90-100% ammonia so rapid deterioration of the exchangers would not occur. No corrosion was observed in sea water saturated with Freon 22 or propane. No differences in alloy performance were evident in any of these tests so selection can be made on the basis of compatibility with sea water. A review of the available literature indicates that 5052 shows the best performance in surface sea water followed by 1100, 3003 and then 6063 alloy. In deep sea water only 5052 and 1100 alloys appear suitable although more data is required. In both surface and deep sea waters, alcladding offers the best protection against tube perforation; few instances of penetration into the core alloy have been observed for the alclad alloys examined in this stud.y.

show abstract

Corrosion of Metals in Tropical Environments. Part 6. Aluminum and Magnesium

Cited by 20 publications

References 2 publications

Atmospheric Corrosion of Magnesium Alloys: Influence of Temperature, Relative Humidity, and Chloride Deposition

Atmospheric Corrosion of Magnesium Alloys: Influence of Temperature, Relative Humidity, and Chloride Deposition

Atmospheric corrosion of magnesium (Mg) alloys

Concurrent studies of enhanced heat transfer and materials for ocean thermal exchangers. Progress report

Contact Info

Product

Resources

About