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Anodising aluminium

Description

This demonstration experiment shows an interesting application of electrolysis. The oxide layer on aluminium foil is made thicker by anodising which improves the metal's corrosion resistance. In the process, the thickened oxide surface coating is coloured by using dyes.

Type of Activity

:
demonstration

Audience

:
Teacher

Age Group

:
11 to 18 years

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
anodising-aluminium



Apparatus Chemicals

Eye protection: goggles

Low-voltage DC power pack, adjustable up to 10 volts (Note 3)

Connecting leads and 4 crocodile clips

Blu-Tak

Paper clips, plastic

Test-tube holder, wooden

Paper tissues

Strip of wood, 15 cm long

Ruler (30 cm)

Beaker (1 dm3)

Beakers (250 cm3), 3

Aluminium foil, approximately 40 cm x 15 cm (Note 1)

Congo Red dye (TOXIC)

Ethanol (HIGHLY FLAMMABLE, HARMFUL)

Dilute sulfuric acid,  approximately 2M (CORROSIVE), 1 dm3

Sodium hydroxide, approximately 1.5M (CORROSIVE), 250 cm3

Propanone (acetone) (HIGHLY FLAMMABLE, IRRITANT) (Note 2)

Refer to Health & Safety and Technical notes section below for additional information.

 









 





This demonstration experiment shows an interesting application of electrolysis. The oxide layer on aluminium foil is made thicker by anodising which improves the metal's corrosion resistance. In the process, the thickened oxide surface coating is coloured by using dyes.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany  Practical Physics  and  Practical Biology .