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Polypyrrole coatings on rheocast aluminum‐silicon alloy: A correlation between properties and electrodeposition conditions
Author(s) -
Eslami Maryam,
Speranza Giorgio,
Deflorian Flavio,
Zanella Caterina
Publication year - 2019
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6709
Subject(s) - polypyrrole , materials science , passivation , alloy , coating , corrosion , electrolyte , silicon , galvanic cell , chromate conversion coating , metallurgy , aluminium , chemical engineering , composite material , electrode , chemistry , layer (electronics) , engineering , polymerization , polymer
The effect of the electrolyte composition and the deposition potential range on the physical properties and possible corrosion protection effect of polypyrrole coatings on rheocast aluminum–2.5 % silicon alloy is investigated. Solutions with different concentrations of sodium nitrate and an electron transfer mediator reagent were used for the electrodeposition. Polypyrrole coating is able to hinder the entrance of electrolyte. Upon the penetration of chloride ions, the coating can induce passivation of the alloy's surface by its reduction. The thickness of the coating and its ion‐barrier properties, controlled by the electrodeposition conditions, are shown as the important factors influencing the protection efficiency. However, localized drastic galvanic coupling at the polypyrrole/aluminum interface forms blisters, causes failure, and limits the possible protection.