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Common Material

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1. Intro

Select the most common material and study each in detail

In each category, explore

  • Physical Properties: Density, melting point, thermal conductivity, etc.
  • Mechanical Properties: Strength, hardness, elasticity, etc.
  • Chemical Properties: Resistance to corrosion, reactivity, etc.
  • Applications: How and where the material is commonly used.

2. Metal

Iron: Fe

  • 8g/cm3
  • 1538 melting
  • Pure iron is soft
  • Mainly used in construction, automobile, tools and machinery

Aluminum

  • 2.7g/cm3
  • 660 melting
  • Moderate strength
  • Form oxide layer protect from further corrosion
  • Mainly used in packaging, transportation, construction, power line

Copper

  • 9g/cm3
  • 1085 melting
  • Moderate strength, very ductile
  • Highly resistant to corrosion
  • Mainly used in wiring, plumbing, jewelry and coins

Stainless Steel: Alloy of Iron, chromium

  • 8g/cm3
  • 1450 melting
  • High strength
  • Excellent corrosion resistance, since chromium content forming a oxide layer
  • Mainly used in cutlery, kitchenware, medical instrucment,

3. Polymers

Polyethylene (LDPE, HDPE)

  • 0.9g/cm3
  • 120 melting
  • soft
  • Excellent resistance to acids
  • Not resistant to oxidizing acids
  • Application
    • LDPE: plastic bag, film wraps, containers
    • HDPE: milk jugs, detergent bottles, piping

Polyvinyl Chloride (PVC)

  • 1.3g/cm3
  • 180 melting
  • Strong and rigid, especially uPVC
  • Can be attacked by some solvents, acids, bases
    • Contain chlorine can be released if burned
  • Application: piping and fitting in construction, electrical calbe

Nylon (Polyamide, PA)

  • 1.12 g/cm3
  • 220 melting
  • High tensile strength and good wear resistance
  • Good resistance to oils, grease and solvents
  • Application
    • Textiles: clothing, ropes, thread
    • Automotive, gears, bushings, belts
    • Consumer: toothbrush bristles, combs, zip ties

3.1. Question

LDPE? HDPE?

  • Low density polyethylene
    • More branched structure
  • High density polyethylene
    • More linear structure

PVC and PE are entirely different polymers

  • Chloride atoms are larger and create stronger intermolecular forces

4. Ceramics

Porcelain: made from kaolin, during firing, some components partially vitrify, turning into glass like substance

  • 2.3g/cm3
  • 1500 melting
  • High compressive strength, but prone to cracking under tension
  • Very hard
  • Application: dishes, pottery, electrical insulators
    • Dental crowns

Glass: from silica, derived from sand, glass does not crystallize

  • 2.5g/cm3
  • 1500 melting
  • Moderate compressive strength, break easily under tension
  • Application: windows, bottles, optical lenses,

Bricks: from clay and shale, rich in Al2O3 and silica

  • 1.8g/cm3
  • 1100 melting
  • Good compressive strength
  • Application: construction of buildings and walls

4.1. Sand

Predominantly composed of silica, due to the abundance of silica in the Earth’s crust

Origin

  • Weathering of rocks, quartz, hard and chemically inert

Quartz is a form of silica, crystalline form

Glass is a product of silica, cooling it rapidly, bypassing the crystalline state

5. Composites

Materials made from two or more constituent materials with different physical or chemical properties

Fiberglass

  • 2.2g/cm3
  • 880 melting
  • Hard, high tensile strength, but can be brittle
  • Application: boats and watercraft, thermal insulation. Automotive body parts

Carbon Fiber-reinforced Polymers(CFRP)

  • 1.8g/cm3
  • Decomposes at high temperature
  • Extremely high strength-to-weight ratio
  • Application: aerospace, sports equipment, construction

Fiber: not a type of material, but the form that many materials can take