IB Design Technology Topic A3.1.5 Chemical Properties of Materials Revision Notes (SL/HL)

IB Design Technology Topic A3.1.5 Chemical Properties of Materials Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Chemical Properties: Only Visible Through a Reaction

A3.1.1 defined the chemical family, so this lesson goes straight to the four properties inside it.
These are the properties that decide where a product can safely live: in a damp bathroom, against acidic food, or near a flame.

Note

Getting these wrong is a safety failure, not just a performance one.
They matter most in food production, construction, aerospace and consumer electronics.
In each of those, exposure to heat, moisture or chemicals can cause the product to fail or to harm its user.

Corrosion Resistance: Standing Up to Air, Water and Salt

Definition

Corrosive Resistance

The ability of a material to resist damage caused by oxidation (like rust) or other chemical reactions with substances such as water, acids, or salts.

Material composition: stainless steel contains chromium, which forms a protective oxide layer on the surface.
Environmental conditions: high humidity and salt speed corrosion up, which is why coastal and marine products corrode fastest.
Protective coatings: paint or galvanising blocks the material from ever meeting the corrosive element.

Tip

Ferrous metals contain iron, so they generally have low corrosion resistance when exposed to moisture and oxygen.
Stainless steel is the exception worth remembering, because it is ferrous yet resists corrosion.
Its chromium content, not its iron content, is what does the protecting.

Stainless Steel in Practice

The chromium oxide layer is self-repairing, so a scratch re-oxidises and closes rather than starting a rust patch.
That is why it is trusted in places where a coating would eventually chip and fail.

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Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

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Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Chemical Properties: Only Visible Through a Reaction

A3.1.1 defined the chemical family, so this lesson goes straight to the four properties inside it.
These are the properties that decide where a product can safely live: in a damp bathroom, against acidic food, or near a flame.

Note

Getting these wrong is a safety failure, not just a performance one.
They matter most in food production, construction, aerospace and consumer electronics.
In each of those, exposure to heat, moisture or chemicals can cause the product to fail or to harm its user.

Corrosion Resistance: Standing Up to Air, Water and Salt

Definition

Corrosive Resistance

The ability of a material to resist damage caused by oxidation (like rust) or other chemical reactions with substances such as water, acids, or salts.

Material composition: stainless steel contains chromium, which forms a protective oxide layer on the surface.
Environmental conditions: high humidity and salt speed corrosion up, which is why coastal and marine products corrode fastest.
Protective coatings: paint or galvanising blocks the material from ever meeting the corrosive element.

Tip

Ferrous metals contain iron, so they generally have low corrosion resistance when exposed to moisture and oxygen.
Stainless steel is the exception worth remembering, because it is ferrous yet resists corrosion.
Its chromium content, not its iron content, is what does the protecting.

Stainless Steel in Practice

The chromium oxide layer is self-repairing, so a scratch re-oxidises and closes rather than starting a rust patch.
That is why it is trusted in places where a coating would eventually chip and fail.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A. Design in theory8 subtopics

B. Design in practice8 subtopics

C. Design in context8 subtopics

IB Design Technology Topic A3.1.5: Chemical Properties of Materials Notes

A. Design in theory8 subtopics

B. Design in practice8 subtopics

C. Design in context8 subtopics

Chemical Properties: Only Visible Through a Reaction

Corrosion Resistance: Standing Up to Air, Water and Salt

Stainless Steel in Practice

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Chemical Properties: Only Visible Through a Reaction

Corrosion Resistance: Standing Up to Air, Water and Salt

Stainless Steel in Practice

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account