Resources Flashcards Preview

Materials > Resources > Flashcards

Flashcards in Resources Deck (36):
1

When did the first processed materials appear

16th Century

2

2 Most abundant elements in the universe

Hydrogen then Helium

3

Most abundant elements in earths crust

Oxygen, silicon, Aluminium

4

Info about crust and its elements

Elements are not evenly distributed, Heavier elements tended to sink under gravity. Lighter minerals in the crust.

5

Most elements are found as...

Minerals ( usually sulphides or oxides)

6

Two mechanisms in mineral formation

Dissolution and precipitation

7

How are small crystallites formed

Rapid Cooling i.e. Under sea volcano sites

8

What is an aggregate?

Sands, gravels, and clays from erosion or mechanical breakdown or rock.

9

Materials in cement

Limestone and Clay

10

What is the cooled cement mixture ground with?

Calcium Sulphate

11

Fine layer of needle like crystals of ___ , forms after 10 mins of cement hydration

Ettringite

12

How was hoover dam cooled?

Using Colorado river as a coolant

13

What are clays made from?

Fine sedimentary particles from weathered rocks. Formed by acidic chemical attack on igneous rocks by rain water weathering

14

How does ZrO2 help toughening ceramics?

When material gets damaged it switched to bulkier form and propagation of the crack is prevented

15

How can you control failure in ceramics?

Lower number of pores or inclusions,
Transformation toughening,
Ceramic fibre composites

16

Main ingredient in glass?

SiO2 (Sand), Trona was used in early glass.

17

What is modern glass made of?

Limestone, dolomite, soda ash

18

What lowers the melting point in the initial glass reaction?

Soda Ash

19

What is molten glass drawn out onto?

Molten tin bath

20

How is glass relieve of its stress after cooling?

Annealed at 200°C

21

How is glass cut?

Using computer controlled diamond cutters

22

How to overcome mechanical weakness of glass?

Lower the defects and pores,
Laminate with polymer layers,
Include metal grid between layers

23

Explain Copper Electrolysis

blister copper dissolves at anode and is reduced at cathode. In CuS04 solution for electrolyte

24

Tin usage

Tin cans prevent corrosion of iron.
Make alloys with copper,
Oxide used as pigments for paints

25

How is iron extracted?

Blast furnace, 40m high steel tower lined with refractory bricks. Air blasted in at base, coke burns releasing heat and CO2, CO2 is reduced to CO which reduces the ore into Pig Iron.

26

Pig Iron

Very brittle because of impurities, these are lowered by beating and open hearth processes

27

Wrought Itron

Puddling removes impurities,
Hitting with hammer drives out slag,
More malleable, less hard

28

How is Aluminium acquired

Caustic soda is added to Bauxite ore which causes aluminium to dissolve. It's then re-precipitated by adding acid

29

What is corrosion?

When a metal reacts with oxygen and water to form a metal oxide

30

Galvanising

Use of zinc as sacrificial anode to passivate corrosion

31

Alloying

Steel with Chromium as chrome oxidises more preferentially to Iron,

32

Extrusion

Beads are melted and forced through a die, die shape indicates product

33

Blow moulding

Hollow tube of polymer goes through mould, air forces plastic to the shape of mould.

34

Injection Moulding

Molten plastic forced into mould under pressure, mould formed in two halves.

35

Making thing plastic sheets

Pressurised plastic tube is heated and blows out like a balloon, balloon is collapsed and trimmed into two layers

36

Methods of plastic moulding

Extruding, Blow moulding, Injection moulding, Thin plastic sheets