Corrosion and Electrodeposition
Corrosion and electrodeposition are applied electrochemical processes in which metals dissolve or are deposited through electrode reactions, governing material degradation and metal coating technologies.
Definition
The branch of applied electrochemistry concerned with the electrochemical dissolution of metals (corrosion) and their electrochemical deposition (electroplating), together with the surface films and methods that control them.
Scope
This area covers the electrochemistry of metal–environment interactions: the spontaneous corrosion of metals through coupled anodic dissolution and cathodic reduction, the deliberate deposition of metals by electroplating, the formation of passive films and protective coatings, and the strategies of corrosion protection. It links thermodynamic stability, electrode kinetics, and surface chemistry to engineering practice.
Sub-topics
Core questions
- How do coupled anodic and cathodic reactions drive the spontaneous corrosion of metals?
- How is metal deposited in a controlled way by passing current through an electrolyte?
- How do passive films and coatings slow or prevent corrosion?
- What thermodynamic and kinetic factors decide whether a metal corrodes or remains protected?
Key theories
- Mixed-potential theory of corrosion
- A freely corroding metal adopts a corrosion potential where the rates of anodic metal dissolution and cathodic reduction (of oxygen or protons) are equal; this corrosion current sets the rate of metal loss.
- Faradaic control of deposition
- In electrodeposition the amount of metal deposited is governed by Faraday's laws, while nucleation, growth, and additives control the morphology, adhesion, and quality of the coating.
Clinical relevance
Corrosion causes enormous economic and safety losses in infrastructure, transport, and industry, while electrodeposition enables protective and decorative coatings, electronics interconnects, and electrowinning of metals; controlling these processes is central to materials engineering and resource use.
History
Faraday's laws of electrolysis (1830s) quantified deposition and dissolution; Evans established corrosion as an electrochemical process in the early 20th century, and Pourbaix's potential–pH diagrams (1940s–1960s) mapped the thermodynamic stability domains of metals.
Key figures
- Marcel Pourbaix
- Ulick R. Evans
- Michael Faraday
Related topics
Seminal works
- jones1996
- paunovic2006
- bard2001
Frequently asked questions
- Is corrosion just rusting?
- Rusting is the specific corrosion of iron and steel; corrosion more broadly is the electrochemical degradation of any metal through coupled oxidation and reduction reactions with its environment.
- How is electrodeposition the reverse of corrosion?
- Corrosion is the spontaneous anodic dissolution of a metal into ions, whereas electrodeposition uses an applied current to reduce metal ions back onto a surface; both are governed by the same electrode reactions and Faraday's laws.