Chem 114 - MSE

Materials Science and Engineering
JAN KENNEY D. GONZALES

(Chemistry Instructor)
Introduction
Historical Perspective
• Beginning of the Material Science– People started to make tools from stone Start of the
Stone Age about two million years ago.
• Five thousand years ago introduce BronzeAge.
• The Iron Age began about 3000 years ago and continues today. The use of iron and steel, a
more durable and cheaper material, changed the daily life of an ordinary person drastically.
• Age of Advanced materials: throughout the Iron Age, many new types of materials have
been introduced (ceramic, semiconductors, polymers, composites).
Classification of Materials
1. Metals
• Materials in this group are composed of one or more metallic elements (such as iron, aluminum,
copper, titanium, gold, and nickel), and often also nonmetallic elements (for example, carbon,
nitrogen, and oxygen) in relatively small amounts. Atoms in metals and their alloys are arranged in
a very orderly manner.
2. Ceramics
• Ceramics are compounds between metallic and nonmetallic

elements; they are most frequently oxides, nitrides, and
carbides.
• For example, some of the common ceramic materials include

aluminum oxide (or alumina,Al2O3), silicon dioxide (or silica,
SiO2), silicon carbide (SiC), silicon nitride (Si3N4), and, in
addition, what some refer to as the traditional ceramics—those
composed of clay minerals (i.e., porcelain), as well as cement,
and glass.
• With regard to mechanical behavior, ceramic materials are

relatively stiff and strong—stiffnesses and strengths are
comparable to those of the metals
3. Polymers
• Polymers include the familiar plastic and rubber materials,

atoms share electrons to form covalent bonding.
• Polymers are soft, pliable, low strength, low density, thermal &
electrical insulators, and optically translucent or transparent.
• Many of them are organic compounds that are chemically

based on carbon, hydrogen, and other nonmetallic elements
(O, N, and Si).
• Some of the common and familiar polymers are polyethylene

(PE), nylon, poly(vinyl chloride) (PVC), polycarbonate (PC),
polystyrene (PS), and silicone rubber.
4. Composites
• A composite is composed of two (or more) individual materials, which come from the categories
(metals, ceramics, and polymers).
• Composites are made of different materials in intimate contact (example: fiberglass, concrete, wood) to
achieve specific properties.
Future of Material Science
Design of materials having specific desired characteristics directly from our knowledge of
atomic structure. The emerging new materials are the following:
1. Miniaturization: Engineered Nanostructured Materials (ENM), with a microstructure

that has length scales between 1 and 100 nanometers with unusual properties.
Electronic components, materials for quantum computing.
2. Smart materials: airplane wings that deice themselves, buildings that stabilize
themselves in earthquakes.
3. Environment-friendly materials: biodegradable or photodegradable plastics, advances

in nuclear waste processing, etc.
Crystals structure of solids
• Crystalline solids a solid that contains a regular and repeating atomic or molecular
arrangement over large atomic distances (long-range order). Examples are metals,
ceramics, and some polymers.
• Non-crystalline Solid, also termed as “amorphous” or “vitreous,” is a solid without long-

range ordering atoms or molecules. Examples are some ceramics and most polymers.
Types of solid materials
1. Atomic solids
• Individual atoms that are held together by

dispersion forces form an atomic solid.
• Their melting and boiling points and heats of

vaporization and fusion are all very low, rising
smoothly with increasing molar mass.
• Examples are solid noble gases.
• Examples of atomic solid; (pure metals, silicon

crystals, and diamond)
2. Molecular solids
• Individual molecules occupy the lattice points.
• Non-polar molecules – dispersion forces

• Polar molecules – dipole-dipole forces and H-bonding
• Molecular solids have higher melting points than the atomic

solids (noble gases).
• Intermolecular forces are still relatively weak, so the melting

points are much lower than those of ionic, metallic, and
• Examples; (sucrose, solid carbon dioxide, water ice, etc.

3. Ionic solids
• The unit cell contains particles with whole, rather

than partial, charges.
• Ionic solids typically have high melting points and

low electrical conductivities.
• Ionic compounds are hard because only a strong

external force can change the relative positions of
many trillions of interacting ions.
• Examples; (table salt, baking soda, lye, and bleach)

4. Metallic solids
• Powerful metallic bonding forces hold individual

atoms together in metallic solids.
• The properties of metals—high electrical and thermal

conductivity, luster, and malleability—result from the
presence of delocalized electrons.
• Metals have a wide range of melting points and

hardnesses, which are related to the packing
efficiency of the crystal structure and the number of
valence electrons available for bonding.
5. Network covalent solids
• Strong covalent bonds link the atoms together throughout a network covalent solid.
• All these substances have extremely high melting and boiling points, but their conductivity
and hardness depend on the details of their bonding.
• Examples are graphite and diamond.

Amorphous solid
• Amorphous solids are non-crystalline.
• Many have small, somewhat ordered regions connected by large disordered regions.
• Charcoal, rubber, and glass are some familiar examples of amorphous solids.
Crystals Structures
• Crystal Structure is the manner in which

atoms, ions or molecules are spatially
arranged.
• Lattice means a three-dimensional array

of points coinciding with atom position
(or sphere centers).
• Unit cell is the basic structural unit or

building block of the crystal structure and
defines the crystal structure by virtue of
its geometry and the atom positions
within.
Crystals Structures
Crystalline Imperfection and Defects
Crystalline imperfections are lattice irregularities

having one or more of its dimensions on the order of
an atomic diameter.
Point Defects associated with one or two atomic

positions.
• A vacancy is a point defect which vacant

lattice site or missing atom from the atomic site. It
may be formed during solidification or by atomic
rearrangement.
• Interstitial/ Self-Interstitial happened to an

atom from the crystal if it is positioned in an
interstitial site between the matrix atoms.
X-ray crystallography
• X-ray diffraction refers to the scattering of X rays by the units of a crystalline

solid. The scattering, or diffraction, patterns produced are used to deduce the
arrangement of particles in the solid lattice.

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Materials Science and Engineering

JAN KENNEY D. GONZALES

• Five thousand years ago introduce BronzeAge.

• Ceramics are compounds between metallic and nonmetallic

• For example, some of the common ceramic materials include

• With regard to mechanical behavior, ceramic materials are

• Polymers include the familiar plastic and rubber materials,

• Many of them are organic compounds that are chemically

• Some of the common and familiar polymers are polyethylene

1. Miniaturization: Engineered Nanostructured Materials (ENM), with a microstructure

3. Environment-friendly materials: biodegradable or photodegradable plastics, advances

• Non-crystalline Solid, also termed as “amorphous” or “vitreous,” is a solid without long-

• Individual atoms that are held together by

• Their melting and boiling points and heats of

• Examples are solid noble gases.

• Examples of atomic solid; (pure metals, silicon

• Individual molecules occupy the lattice points.

• Non-polar molecules – dispersion forces

• Molecular solids have higher melting points than the atomic

• Intermolecular forces are still relatively weak, so the melting

• Examples; (sucrose, solid carbon dioxide, water ice, etc.

• The unit cell contains particles with whole, rather

• Ionic solids typically have high melting points and

• Ionic compounds are hard because only a strong

• Examples; (table salt, baking soda, lye, and bleach)

• Powerful metallic bonding forces hold individual

• The properties of metals—high electrical and thermal

• Metals have a wide range of melting points and

5. Network covalent solids

• Examples are graphite and diamond.

• Amorphous solids are non-crystalline.

• Crystal Structure is the manner in which

• Lattice means a three-dimensional array

• Unit cell is the basic structural unit or

Crystalline imperfections are lattice irregularities

Point Defects associated with one or two atomic

• A vacancy is a point defect which vacant

• Interstitial/ Self-Interstitial happened to an

• X-ray diffraction refers to the scattering of X rays by the units of a crystalline

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