http://ceramics.org/learn-about-ceramics/

Ceramic in Aerospace

Ceramic in Construction

Ceramic Science

MTLS 4RO3

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Lectures time and location

Tannaz Javadi

• Lectures take place at ETB 230

• Time: Mondays

• 7:00-8:15 pm, 8:30-9:45 pm, 15 min break

• E-mail: tannaz.javadi@gmail.com

• TA: Wenting Li (Renee)

• Office hours: Mondays, 2:00-4:00 pm, JHE 356

• E-mail: liw33@mcmaster.ca

Evaluation • Midterm: 30 % (Oct. 21st) • Seminar and Report: 40 % o 15% Presentation, 15% Scientific Report, 10% asking question and

evaluating your fiends

• Final: 30 %

Textbook • “Physical Ceramics”, Chiang, Birnie, Kingery, Wiley • “Ceramic Processing and Sintering”, M. N. Rahaman

Seminar and Report

Topic selection: Try to schedule it as soon as possible • Pick a ceramic material of your choice – choose wisely • Suggestion:

o nothing commonplace o Pick a cutting edge technology (new material, new process, new application) o Pick a recent development in a specific area and use this as a launching point

• Forward your choice to your instructor for verification and tracking • Deadline for topic OCT. 7th • Presentation marked by instructor, TA, and peers. • Last 2-3 days of class – full day will be devoted to presentations (no lecture) • Paper submitted a week before your presentation

Paper • Maximum 10 pages (excluding appendices) • Review papers that included in your presentation • Supporting documentation is required • More detail and more technical than presentation

Presentation • 20 minutes in length & 5 minutes for questions • HAVE SOME FUN WITH THIS! • Picture yourself in an industrial ceramics environment • Why your company should pursue research and development in the field of your specific ceramic material • Technical-minded • Tie in concepts and topics discussed in class • Discuss the future: technology, developments, applications, etc. • Need visual aids (can’t be all text) (Pictures, diagrams, CAD or hand drawn schematics, etc. )

PRESENTATION MARKING FORMAT

MATLS 4R03 PowerPoint Presentation Marking Sheet Evaluator:_________________________ Student:_________________________ Design Clear introduction, body and conclusion present 1 2 3 4 5 PowerPoint elements used well text, graphics, sound, animation where appropriate 1 2 3 4 5 Quality of font choices, colour schemes, sizes and styles 1 2 3 4 5 Content Information is relevant and interesting 1 2 3 4 5 Students have used creativity 1 2 3 4 5 Sufficient literature review 1 2 3 4 5 Correct punctuation, complete sentences, grammar spelling 1 2 3 4 5 Presentation The presentation is fluent from beginning to end 1 2 3 4 5 Students demonstrate familiarity with material, process and/or application 1 2 3 4 5 Student makes good eye contact and speaks clearly using appropriate language 1 2 3 4 5 Answering the questions 1 2 3 4 5

History of Ceramics 26,000 B.C. Early man discovers

that clay, consisting of mammoth fat and

bone mixed with bone ash, can be molded and dried in the sun

to form a brittle, heat resistance material.

Thus begin CERAMIC art.

6,000 B. C. Ceramic firing is first

used in Ancient Greece. The Greek pottery, Pithoi, is

developed and used for storage, burial,

and art.

4,000 B. C. GLASS is discovered

in ancient Egypt. This primitive glass

consisted of a silicate glaze over a

sintered quartz body and was primarily used for jewelry.

50 B. C. -50 A. D. Optical glass (lenses and

mirrors), window glass and glass

blowing production begins in Rome and spreads around the world with Roman

600 A. D. Porcelain, the first ceramic composite,

is created by Chinese. This

durable material is made by firing clay along with feldspar

and quartz. Porcelain is used in electrical insulators,

to dinnerware.

History of Ceramics

1870’s Refractory materials (able to withstand extremely high temperatures) are introduced during the Industrial revolution. Materials made from lime

and MgO are used for everything from bricks for buildings to lining the inside of steel making furnace.

1877

The first example of high-

tech materials research is directed

by inventor Thomas Edison. Edison

tests a plethora of ceramics for resistiv-

ity, for use in his newly discovered car-

bon microphone.

1889

The American Ceramic

Society was founded by Elmer

E. Gorton, Samuel Geijsbeek and

Colonel Edward Orton Jr.. The primary

goal of this society continues to be

unlocking the mysteries of high-tech

ceramics.

American Ceramic Society

735 Ceramic Place

Westerville, Ohio 43081-8720

614-890-4700

1960

With the discovery of the

laser and the observation that

its light will travel through glass,

a new field called fiber optics opens.

Fiber optic cable allows light pulses to

carry large amounts of information with

extremely low energy loss. The development of photo-

voltaic cells which convert light

into electricity opens a new way to

access solar energy.

1987

Scientists discover a

superconducting ceramic oxide

with a critical temperature of 92K,

surpassing the old metallic super-

conductor’s critical temperature by

over 60K. A potential application of

ceramic superconductors is in inte-

grated circuits in new high speed

computers.

1992

Certain ceramics known

as “smart” materials are widely

publicized. These materials can sense

and react to variable surface conditions,

much like a living organism. For exam-

ple, air bags in cars are triggered by a

“smart” sensor which intercepts a pres-

sure signal when the car is hit and

transforms it into an electrical im-

pulse that inflates the bag.

1965

1877, Thomas Edison tests a plethora of ceramic for resistivity, for use in his newly discovered

carbon microphone

1889, The American Ceramic Society was founded by Gorton, et. al.. The primary goal of this society continues to be unlocking the mysteries of high-

tech ceramics

1960 Fiber

Optics

1965 Photo voltaic cells

1987 Superconducting

ceramic oxide

Future ceramics

Ceramics

• Refractory • Inorganic • Non-matallic • Covalent or Ionic • Brittle • Corrosion resistance • Hard • Example: Metal Oxide (Binary (FeO), Complex (BaTiO3)) Carbides Nitrides Silicates

Ceramics properties

IC packages Thermal insulations • Thermal conductivity:

• Electrical conductivity • Mostly brittle • Wear resistance - high hardness

•Magnetic properties

• Insulators (Porcelain) • Semiconductors (Carbides: SiC) • Superconductors (Cu2O)

Properties

Process Structure

Types of Bonding Covalent – Directional: constrained by the electron orbital configuration

Diamond: Carbon- 1S2 2S2 2p2 1S2 2(Sp3)

Tetrahedron: 109.5° Four orbits equally spaced in 3D Directionality Shared electrons Silica: SiO2

Si- 1S2 2S2 2p6 3S2 3p2 3(Sp3)

O- 1S2 2S2 2p4 2(Sp3)

Ionic – Nondirectional: electrostatic attraction is equally favorable in all directions

Hybridized

Hybridized

Hybridized

1.7

50

100

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per

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Difference in electronegativiy

Ionic

Covalent

Types of Bonding

Crystal Structure Closed packed lattices:

A sequential stacking of planar layers of closed packed atoms

FCC: ABCABC layers

HCP: ABABAB layers

Octahedral

8 Sides & 6 Vertices Centered exactly halfway

between the adjacent atoms

Tetrahedral

4 sides & 4 Vertices Closer to the base plane of

tetrahedron and slightly off the adjacent atoms.

Interstitial sites

• Polyhedral cavities between any two adjoining packed layers of atoms

FCC Number of atoms: 4 Number of octahedral sites: 4 Number of tetrahedral sites: 8

Ratio of octahedral sites to atoms: 4/4→ 1:1 Ratio of tetrahedral sites to atoms: 8/4→ 2:1

HCP Number of atoms: 2 Number of octahedral sites: 2 Number of tetrahedral sites: 4

Ratio of octahedral sites to atoms: 2/2→ 1:1 Ratio of tetrahedral sites to atoms: 4/2→ 2:1

FCC and HCP lattices have the same number density of octahedral and tetrahedral sites

Interstitial sites

Stability of Ionic crystal structures

r R

E(ev)

0 R0

Repulsive

Attractive

• The energy of the crystal is lower than that of the free atoms by an amount equal to the energy required to pull the crystal apart into a set of free atoms. – NaCl is more stable than a

collection of free Na and Cl.

Zi and Zj= Ion charges e= Electron charge Ɛo= permittivity of free space Bij= Empirical constant Rij= Interatomic seperation Ro= equilibrium seperation n has a value of 10

Crystal with N ion pairs

Stability of Ionic crystal structures

For MX compound - Zc=Cation valence - ZA= Anion valence - Rij= xijRo

- Ro= minimum possible separation (Ro= RA+RC) - α= Madelung constant= The summation of the electrostatic interactions - α>1 for stable crystals

E whole crystals << E corresponding single pairs of ions

Close value of α= polymorphism ---- Zincblende & Wurtzite

α= 1.638 α= 1.641

Pauling’s Rules

Predict the crystal structure

Electrostatic stability Geometric stability- Assume ions as hard spheres

1) Coordination of cations with anions Cations are usually smaller than anions and rC/rA is less than unity. Cations and anions prefer to have as many neighboring ions as possible. Stable ceramic crystal is when those anions surrounding a cation are all in contact with that cation. The coordination number depends on the cation-anion (rC/rA) radius ratio. For a specified coordination number, there is a critical or minimum rC/rA ratio, which can be calculated by geometrical methods.

W.D. Kingery, H.k. Bowen, and D. R. Uhlmann, “Introduction to ceramics”, 2nd edition, 1976, John wiley & Sons, New York.

Coordination numbers and Geometries

Tetrahedra Octahedra

2) Preserve local charge neutrality

For NaCl

1/6 of the Na cation charge (+1) is allocated to each of the chlorine anions therefore each chlorine anions should be coordinated with 6 Na cations to satisfy its -1 valence.

Pauling’s Rules

3) Coordination polyhedra prefer maximum separation

• Linked by 1. corners, 2. edges, and 3. faces 4) Importance of rule 3 goes up as coordination number gets smaller

and cation valence gets higher. 5) Simple structures preferred over complex ones.