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http://ceramics.org/learn-about-ceramics/
Ceramic in Aerospace
Ceramic in Construction
Ceramic Science
MTLS 4RO3
Skiing sm
arter with
p
iezoelectric fib
res
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: [email protected]
• TA: Wenting Li (Renee)
• Office hours: Mondays, 2:00-4:00 pm, JHE 356
• E-mail: [email protected]
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
Ion
ic o
r co
vale
nt
per
cen
t
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.