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Особенности развития коррозионного процесса на поверхности сплавов магния

Особенности развития коррозионного процесса на поверхности сплавов магния

Abstract

It has been ascertained that development of the corrosion process on the surface of magnesium alloys MA8 (Mg–Mn–Се system) and VMD10 (Mg–Zn–Zr–Y) in the chloride containing solution is determined by the composition and the structure of the alloy. The key factor of the corrosion activity of the investigated samples is the occurrence of the microgalvanic couples on the sample’s surface. Greater corrosion resistance of the MA8 alloy in comparison with the VMD10 alloy has been investigated by the scanning vibrating probe method (SVP). The reason of this effect is the less amount of the secondary phases being the cathodic parts of the alloy relative to the base matrix. At the same time the secondary phases in the VMD10 alloy have more positive potential in the corrosion-active media in comparison with α-phase of magnesium that leads to the acceleration of the dissolution of the α-phase. The data obtained by the mutually independent methods have a good correlation with each other and confirm greater corrosion activity of the VMD10 alloy in comparison with the MA8 alloy. The analysis of the experimental data obtained by SVR methods, optical microscopy, gravimetry and volumetry indicates a high corrosion activity of magnesium alloys irrespective of the type and method of technological processing even in the weak-concentrated chloride media. The results of the data obtained testify about the impossibility of the practical usage of the magnesium alloys without the addition methods of the anticorrosion protection (as far as the protection may be of various types – anti-wear, anti-fouling, anti-friction, etc.) even in the weekly active corrosion environment.

Установлено, что развитие коррозионного процесса в хлоридсодержащей среде на поверхности сплавов магния МА8 (система Mg–Mn–Се) и ВМД10 (Mg–Zn–Zr–Y) определяется составом и структурой сплава. Ключевой фактор коррозионной активности исследуемых сплавов – возникновение микрогальванопар на поверхности образца. Методом сканирующего вибрирующего зонда установлено более высокое, по сравнению со сплавом ВМД10, сопротивление коррозии сплава МА8. Причиной этого является наличие в его составе меньшего количества вторичных фаз, служащих катодами по отношению к основной матрице. При этом вторичные фазы в сплаве ВМД10 в коррозионно-активной среде имеют потенциал более положительный по отношению к α-фазе магния, тем самым ускоряя процесс ее растворения. Данные, полученные взаимонезависимыми методами, согласуются между собой и подтверждают более высокую коррозионную активность сплава ВМД10. Методами SVP, оптической микроскопии, гравиметрии и волюмометрии показана высокая коррозионная активность магниевых сплавов, вне зависимости от марки и способа технологической обработки, даже в слабосоленых хлоридных средах. Результаты свидетельствуют о невозможности практического использования магниевых сплавов без дополнительной антикоррозионной (поскольку защита может быть противоизносная, антиобрастающая, антифрикционная и т.д.) защиты даже в слабоактивных коррозионных средах.

Keywords

МАГНИЕВЫЕ СПЛАВЫ, КОРРОЗИЯ, ЭЛЕКТРОХИМИЯ, МЕТОД СКАНИРУЮЩЕГО ВИБРИРУЮЩЕГО ЗОНДА, ГРАВИМЕТРИЯ, ВОЛЮМОМЕТРИЯ, СКОРОСТЬ КОРРОЗИИ

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
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