On-demand release of corrosion-inhibiting ions from amorphous Al-Co-Ce alloys.
Controlled release technologies are often used to supply chemicals or drugs at given rates. Release often occurs on contact with solution. However, some applications, such as corrosion protection, require containment of the active species in a reservoir and their slow release when needed. Conductive polymers have been used as reservoirs for corrosion inhibitors whose triggered release occurs by galvanic reduction or ion exchange. This work shows one of the first examples of pH-controlled release of corrosion-inhibiting ions from an amorphous metallic coating where the pH change that triggers release is a consequence of the onset of corrosion. This corrosion-inhibition strategy provides further corrosion protection beyond the traditional roles of barrier and sacrificial cathodic protection using a metal coating. For instance, zinc galvanizing provides sacrificial cathodic protection and acts as a barrier, but does not supply inhibitor ions. In the coating described here, protection of an underlying structural alloy exposed at coating defects is demonstrated by inhibitor ion release in addition to barrier function and sacrificial cathodic protection.
Jakab
M A
MA
The Center for Electrochemical Science and Engineering, Department of Material Science and Engineering, University of Virginia, 116 Engineer's Way, Charlottesville, Virginia 22904-4741, USA.
Scully
J R
JR
D000497:Alloys / Q000032:analysis / Q000737:chemistry*; D017607:Aluminum Compounds / Q000032:analysis / Q000737:chemistry*; D002586:Cesium / Q000032:analysis / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003035:Cobalt / Q000032:analysis / Q000737:chemistry*; D003343:Corrosion; D004058:Diffusion; D004563:Electrochemistry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008422:Materials Testing; D008968:Molecular Conformation; D013499:Surface Properties
D000497:Alloys; D017607:Aluminum Compounds; D020099:Coated Materials, Biocompatible; D007477:Ions; D002586:Cesium; D003035:Cobalt