Glass

Question 1

What are the key properties of glass?

Answer 1

Transparent
High stiffness
Brittle
Strong in compression
Weak in tension
Hard
Fracture produces sharp surfaces
Excellent corrosion resistance
Low leaching of contaminants

Question 2

What are the possible properties of glass composites

Answer 2

Improved tensile strength
Heat resistance
Noise dampening
High impact resistance
Light + heat transmission

Question 3

What kind of material is glass?

Answer 3

Non-crystalline

Amorphous

Question 4

How is glass produced from its liquid state?

Answer 4

Continuous cooling

Question 5

What is the basic building block for glass?

Answer 5

SiO4 tetrahedron he’s together with covalent bonds

Question 6

How does glass maintain its amorphous liquid phase structure?

Answer 6

By being supercooled into a solid

Question 7

Why is glass higher in silica purity less viscous?

Answer 7

Less molecules disrupting structure

Question 8

Increased viscosity [] ability to form a [] solid

Answer 8

Inhibits ability

Crystalline solid

Question 9

What type of glass has the lowest viscosity?

Answer 9

Soda lime glass

Question 10

How does alkali addition affect the microstructure of glass?

Answer 10

Breaks up the structure

Covalent bonding distances and angles break up the structure

Question 11

As alkali are added, which kind of oxygen atoms form?

Answer 11

Ionic Non-bridging oxygen atoms

Question 12

When referring to bridging oxygen atoms what does x mean in Qx

Answer 12

The number of bridging oxygens in the tetrahedron

Question 13

Low levels of sodium give []
While higher ones give []

Answer 13

Q3

Q2

Question 14

What does sodium saturation do to the SiO4 tetrahedron?

Answer 14

Make it unable to anything else

Oxygen bonds are broken

Question 15

In the schematic microstructure of glass, which elements are network formers?

Answer 15

Si

Al

Question 16

In the schematic microstructure of glass, which elements are network modifiers?

Answer 16

Na

Ca

Question 17

What is a network modifier?

Answer 17

Breaks glass structure, causes amorphous form

Question 18

What raw materials go into glass?

Answer 18

Glass sand
Alumina sand
Soda ash
Limestone
Dolomite

Question 19

In commercial glass, SiO2 makes up how much?

Answer 19

70-74%

Question 20

In commercial glass, Na2O makes up how much?

Answer 20

12-16%

Question 21

In commercial glass, CaO makes up how much?

Answer 21

5-11%

Question 22

What molecules make up 1-3% of commercial glass?

Answer 22

Mg

Al2O3

Question 23

What are the five glass components?

Answer 23

Glass forming oxides

Meting temp/ reducing fluxes

Property modifiers

Tinting glass

Processing agents

Question 24

Glass strength is dependent on

Answer 24

Largest surface flaw

Question 25

What does glass polishing reduce?

Answer 25

Surface flaws

Question 26

Abraded glass has lower what than flame polished glass?

Answer 26

Strength

Question 27

What are the three zones made on the surface of a glass fracture?

Answer 27

Mirror zone Must zone Hackle zone

Question 28

What is the mirror zone like?

Answer 28

Smooth surface near fracture origin

Question 29

What is the most zone lime

Answer 29

Small band of rougher surface between mirror and hackle zones

Question 30

What is the hackle zone like?

Answer 30

Large irregularly oriented faceted area

Question 31

What happens to the strength of glass under load over time?

Answer 31

Decreases - static fatigue

Question 32

What can the strength decrease caused by static fatigue be bolstered by?

Answer 32

Temp and humidity

Question 33

Why is the tensile strength of glass reduces underwater

Answer 33

Si-O-Si bonds at crack tip are more reactive to water when stretched

Question 34

Underwater, rapid loading drives cracks [] than water can [] into the cracks. Resulting in []

Answer 34

Faster Diffuse Increased strength

Question 35

How much if flat glass is raw material?

Answer 35

80% the rest is recycled glass

Question 36

What are the steps of the glass manufacturing process?

Answer 36

Weighing + mixing Melting Float Annealing lehr Inspection Cutting + storage

Question 37

What temp is glass melted at?

Answer 37

1600°C

Question 38

What happens to the heat wasted in glass melting?

Answer 38

It is recovered to warm up combustion air

Question 39

In glass melting water cooled stirrers make . . .

Answer 39

The melt homogenous

Question 40

In the glass float

Answer 40

Molten glass floats on a bath of molten tin

Question 41

What kind of atmosphere makes it so tin doesn’t oxidise?

Answer 41

Inert 95% nitrogen atmosphere

Question 42

Glass enters the float at what temp and leaves the float as a uniform ribbon at what temp?

Answer 42

1050°C 600°C

Question 43

How is laminated glass produced?

Answer 43

By bonding two or more layers with a plasticised inter layer

Question 44

Laminated glass has a [] refractive index to glass

Answer 44

Similar

Question 45

Laminated glass absorbs how much of the sun’s UV?

Answer 45

99%

Question 46

What happens in the annealing lehr?

Answer 46

Glass slowly cooled to prevent stress buildup Done with use of rollers

Question 47

What is tinted glass capable of?

Answer 47

Controlling heat and light transmission

Question 48

What is wired glass capable of?

Answer 48

Fire resistance, safety glazing

Question 49

What are the uses of glass in construction?

Answer 49

Flat glass Laminated glass Blocks Composite fibre panels Used as a SCM Polymer/resin bonded glass products