Prevention of rusting

What can you observe in the picture?

• Diving suit

• Protective suits

Answer explanation

Firefighters use protective suits to prevent themselves from being hurt, similar to metals.

Metals need protective layers to prevent themselves from rusting.

What is this method for prevention of rusting

• Paint

• Grease and oil

• Plastic coating

• Using other metals

Answer explanation

Paint are usually used for fences, cars and bridges

How do we prevent car engines from rusting?

• Paint

• Oil or grease

• Plastic coating

• Using other metals

Answer explanation

Car engines usually uses oil or grease to prevent rusting

Rather than using paint, give another method to prevent wire fences from rusting

• Oil or grease

• Plastic coating

• using other metals

Answer explanation

Plastic PVC coating can effectively prevent wire fences from rusting

Based on the electrochemical series, is Zinc (Zn) more electropositive than Iron (Fe)

• Yes

• No

Answer explanation

Galvanisation process, iron or steel is galvanised with a thin layer of zinc (Zn).

Zinc oxide (ZnO), hard, strong, non porous, protects the iron.

What are the other two types of plating besides zinc plating?

• Tin

• Chrome

• Copper

• Gold

Tin oxides protect iron from what?

(a)  

Answer explanation

Even though iron is more electropositive than tin, but coating the iron with a layer of tin can effectively prevent the iron to have contact with air and moisture.

PS: Tin platting is affordable

What are those small little plates on the ship made of?

• Zinc

• Gold

• Tin

• Copper

Answer explanation

Zinc is more electropositive than Iron, hence Zinc acts as a sacrificial metal to protect iron from corrosion and rusting.

How??

• Godzilla??

• 
• Standing on the submarine!!

• Long footed!

Answer explanation

Magnesium (Mg) is more electropositive than Iron (Fe). Hence it acts as a sacrificial protection for the steel pillars for oil rigs.

Stainless steel is an alloy made from

• Iron

• Chromium

• Nickel

• Carbon

• Hydrogen

Answer explanation

Chromium and nickel create a shiny, protective and corrosion proof oxide layer.

Stainless steel is widely used in surgical instruments and kitchen utensils.