Corrosion Behavior of Mg-Al Alloys with Aluminum Thermal Spray Coatings in Humid and Saline Environments
Arrabal, R. Pardo, A. Merino, M.C.
Corrosion Behavior of Mg-Al Alloys with Aluminum Thermal Spray Coatings in Humid and Saline Environments - dic. 2009 - 14 p. ; 817-830
Transcripción del resumen del autor. The corrosion behavior of thermal spray aluminum coatings deposited on AZ31 (UNS M11311), AZ80 (UNS M11800), and AZ91D (UNS M11916)Mg-Al alloys was evaluated in salt water (3.5 wt% sodium chloride [NaCl]), neutral salt fog (ASTM B117), and high relative humidity (98% RH, 50°C) environments. The changes in the morphology and corrosion behavior of the aluminum coatings induced by cold-pressing posttreatment were also examined. In chloride-containing environments, the presence of interconnected pores in the as-sprayed aluminum coatings facilitated the galvanic acceleration of the corrosion of the magnesium substrates. The cold-pressed aluminum coatings revealed improved corrosion behavior associated with a lower level of porosity. In high-humidity environments, even though the corrosion rates for all the examined materials were lower than in the case of salt fog, similar corrosion features were observed; formation of hydromagnesite on the surface of untreated materials, galvanic corrosion in the Al-TS specimens, and almost negligible corrosion attack of the aluminum coating with formation of bayerite (ß-Al2O3·3H2O) in the case of the cold-pressed specimens.
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Corrosion Behavior of Mg-Al Alloys with Aluminum Thermal Spray Coatings in Humid and Saline Environments - dic. 2009 - 14 p. ; 817-830
Transcripción del resumen del autor. The corrosion behavior of thermal spray aluminum coatings deposited on AZ31 (UNS M11311), AZ80 (UNS M11800), and AZ91D (UNS M11916)Mg-Al alloys was evaluated in salt water (3.5 wt% sodium chloride [NaCl]), neutral salt fog (ASTM B117), and high relative humidity (98% RH, 50°C) environments. The changes in the morphology and corrosion behavior of the aluminum coatings induced by cold-pressing posttreatment were also examined. In chloride-containing environments, the presence of interconnected pores in the as-sprayed aluminum coatings facilitated the galvanic acceleration of the corrosion of the magnesium substrates. The cold-pressed aluminum coatings revealed improved corrosion behavior associated with a lower level of porosity. In high-humidity environments, even though the corrosion rates for all the examined materials were lower than in the case of salt fog, similar corrosion features were observed; formation of hydromagnesite on the surface of untreated materials, galvanic corrosion in the Al-TS specimens, and almost negligible corrosion attack of the aluminum coating with formation of bayerite (ß-Al2O3·3H2O) in the case of the cold-pressed specimens.
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