Influence of Embedded
Nanocontainers on the Efficiency of Active Anticorrosive Coatings
for Aluminum Alloys Part II: Influence of Nanocontainer Position
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Abstract
The present work contributes to the coating design of
active anticorrosive coatings for the aluminum alloy, AA2024-T3. Part
II is a continuation of Part I: Influence of Nanocontainer Concentration
and describes further surprising aspects of the design of nanocontainer
based active anticorrosive coatings, which influence their performance.
The studied coating system consists of a passive sol–gel (SiO<sub><i>x</i></sub>/ZrO<sub><i>x</i></sub>) matrix
and inhibitor (2-mercaptobenzothiazole) loaded mesoporous silica nanocontainers
(MBT@NCs), which are dispersed only in half of the coating volume.
Varying position and concentration of MBT@NCs the synergetic effect
of inhibitor amount and path length on the metal surface were analyzed,
considering the balance between optimum barrier properties, active
protection and adhesion. The impact of MBT@NC position on passive
and active corrosion resistance was investigated by electrochemical
impedance spectroscopy and scanning vibrating electrode technique.
Increasing the distance between MBT@NCs and metal surface led to better
barrier properties but worse active corrosion inhibition. These findings
improve the understanding of the factors influencing the overall performance
of active anticorrosive coatings and enable the development of a coating
system with optimum anticorrosion efficiency