Anodizing of Aluminum
2Al + 3H2O → Al2O3 + 6H+ + 6e−
Overview
Anodizing grows a thick, porous aluminum oxide layer on aluminum surfaces by making the aluminum the anode in an acid electrolyte (typically 15–20% H₂SO₄). The oxide layer (5–25 μm for decorative, up to 150 μm for hard anodizing) provides corrosion resistance, wear resistance, and can absorb dyes for coloring.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Aluminum Al | 2 | (s) |
| Reactant | Water H₂O | 3 | (l) |
| Product | Aluminum Oxide Al₂O₃ | 1 | (s) |
Everyday Example
Apple MacBooks, iPhones, and many premium electronics use anodized aluminum for the durable, colored finish.
Industrial Importance
Anodizing is used in aerospace, architecture, automotive, and consumer electronics. The market exceeds $4 billion annually.
Properties
- Type
- Electrochemical
- Reversible
- No
- Energy
- Endothermic
- ΔH
- 871.0 kJ/mol
Related Reactions
Alkaline Battery Discharge
Cathodic Protection (Zinc Sacrificial Anode)
Chlor-Alkali Electrolysis
Chrome Electroplating
Copper Electroplating
Daniell Cell (Zinc-Copper Galvanic Cell)
Electrochemical CO₂ Reduction to CO
Electrochemical Machining (ECM)
Electrolysis of Molten NaCl (Downs Process)
Electrolysis of Water
Frequently Asked Questions
What is the equation for Anodizing of Aluminum?
The balanced equation is: 2Al + 3H₂O → Al₂O₃ + 6H⁺ + 6e⁻.
What type of reaction is Anodizing of Aluminum?
Anodizing of Aluminum is a electrochemical reaction.
Is Anodizing of Aluminum exothermic or endothermic?
Anodizing of Aluminum is endothermic (absorbs energy). The enthalpy change (ΔH) is 871.0 kJ/mol.