Traditional Ceramic Products Are China, Dental Porcelain, And Sanitary Ware

MFGT 290 MFGT Certification Class Professor Joe Greene CSU, CHICO MFGT 290 Chapters 13, 14, and 15: Engineering Materials- Plastics, Composites, and Ceramics

Chap 13: Plastics
Plastics
Polymerization
Polymer Structures
Thermoplastics
Engineering Thermoplastics
Thermoset Polymers
Processing of Plastics
Review Questions

Definition of Plastics All Materials Gases Simple Liquids Solids Metals Polymers (polymeric molecules) Ceramics Thermosets Heat Setting Thermoplastics Heat Forming Elastomers Plastics Rubbers Fiberglass Resins

Introduction
Polymeric materials can be either
Thermoplastics, thermosets, and elastomers.
Each section is presented in appropriate groups
Thermoplastics- Heat Forming materials (Can reheat & form again)
Carbon bonds are Saturated and are single bonds.
Come in a variety of forms
Pellets, powder (1-100 microns), flake, chip, cube, dice,
Shipped in packages of choice
Bags (50 lbs), drums (200 lbs), boxes, cartons, gaylords (1000 lb),
Tank-truck loads (15 tons), rail cars (40 – 80 tons)
Bulk supplies are stored in silos and conveyed pneumatically
Thermosets- Heat Setting materials (Once set can’t reform -like cooked eggs)
Carbon bonds are Unsaturated and have some double bonds.
Supplied in powder or liquid form
Supplied in drums, tank-trucks, and railroad cars.
Rubbers are supplied in bale form.

Commercial Thermoplastics
Olefins
Unsaturated, aliphatic hydrocarbons made from ethylene gas
Ethylene is produced by cracking higher hydrocarbons of natural gas or petroleum
LDPE commercialized in 1939 in high pressure process
Branched, high pressure, and low density polyethylene
HDPE commercialized in 1957 in low pressure process
Linear, low pressure, high density
Medium density PE and other PE, UHMWPE, LLDPE
The higher the density the higher the crystallinity
Higher the crystallinity the higher the modulus, strength, chemical resistance,
PE grades are classified according to melt index (viscosity) which is a strong indicator of molecular weight.
Injection molding requires high flow, extrusion grade is highly elastic, thermoforming grade requires high viscosity or consistency
Other commodity (cheap) plastics
PP, PS, PVC (or vinyl), ABS, PMMA (Acrylic)

Major Plastic Materials 1994
LDPE 6.4 M metric tons
HDPE 5.3 M metric tons
PVC 5.1 M metric tons
PP 4.4 M metric tons
PS 2.7 M metric tons
PU 1.7 M metric tons
PET 1.6 M metric tons
Phenolic 1.5 M metric tons
Total 28.6 M metric tons (82% of market)

Recycling of Plastics
State and Federal Legislation
PET bottle recycling
Codes for plastics
1 PET
2 HDPE
3 Vinyl/PVC
4 LDPE
5 PP
6 PS
7 Other

Amorphous- Molecular structure is incapable of forming regular order (crystallizing) with molecules or portions of molecules regularly stacked in crystal-like fashion.
A - morphous (with-out shape)
Usually transparent (Clear bags)
Less shrinkage with amorphous materials.
States of Thermoplastic Polymers
Amorphous Polymers
ABS Acrylics
Polycarbonate PS
Polyurethanes PPO
Phenoxy PVC
SAN

Crystalline- Molecular structure forms regular order (crystals) with molecules or portions of molecules regularly stacked in crystal-like fashion.
Most crystalline polymers are semi-crystalline because very few plastics are 100% crystalline. All have both regions that are crystalline and some that are amorphous
Usually Opaque and not transparent
More molding shrinkage with
crystalline materials.
States of Thermoplastic Polymers
Crystalline Materials
LDPE HDPE PP
PET PBT
Polyamides
PMO PEEK
PPS PTFE
LCP (Kevlar)

Functional Groups
Certain chemical characteristics associated with various groups of atoms, called functional groups.
Particular groups of atoms occur in a large molecule, the characteristic chemistry is anticipated.
Example, PP has Functional groups can be attached to basic groups of carbon atoms by replacing on H atom.
Note: PP is Mostly Isotactic- CH 3 on one side of polymer chain (isolated). Commercial PP is 90% to 95% Isotactic and not Atactic (random) or syndiotactic
C C H CH 3 H H n C C H CH 3 H H n C C H CH 3 H H n C C H CH 3 H H n

Functional Groups
Various molecules of carbon, hydrogen and oxygen illustrating the differences properties with different atomic arrangements
isopropyl alcohol- rubbing alcohol
methylethyl ether- anesthetic
acetone- common solvent
methyl acetate- sweet chemical perfume
propionaldehyde- sharp smelling chemical
propanoic acid= related to vinegar
Aromatic group- PBT, PET, PC, PEEK, PS all have aromatic
6 carbon atoms bonded together with double bonds
Highly aromatic if have several aromatic groups
Aliphatic group- LDPE, HDPE,
single and double bonded carbons with other atoms

Polymers Units
Just as 2 carbons atoms are bonded together in ethane, three, four, or more carbons can be bonded in chain-like arrangement, sometimes thousands of atoms long.
Long chains of atoms are poly-mers (many-mers or units)
Figure
Polyethylene PP PS PVC
Note: PP is Mostly Isotactic- CH 3 on one side of polymer chain (isolated). Commercial PP is 90% to 95% Isotactic and not Atactic (random) or syndiotactic
C C H H H H n C C H CH 3 H H n C C H Cl H H n C C H H H n

Complex Polymers
Polymer chains with atoms other than carbon
Usually polymer chains with C and N, O, S, F, and Cl
PVC has Cl; Nylon has O and N; Polyurethane has O and N
PET has O and benzene ring; PC has O and benzene ring
Bonding in Plastics (No metallic or Ionic bonds_ Just Covalent)
Covalent bonds are dominate bonding between C and other atoms.
Secondary bonding and Intermolecular Forces
Van der Waal’s Forces- weak attraction not in plastics
Dipole interactions- Part of molecule is more electronegative than other part causing one side to be partially negative and the other partially positive.
Hydrogen bonding - Very important for some plastics- Like Nylon
Causes physical properties to change. Like tensile strength and melting point
Nylon 6 has higher tensile strength and melting point than Nylon 12 because
Nylon 6 has 1 dipole + 1 hydrogen bond for every 6 Carbon atoms in chain.
Nylon 12 has 1 dipole and 1 hydrogen bond every 12 Carbon atoms
Dipole induces polarity and occurs if
C-Cl single bond (like PVC); C-Fl single bond (Like PTFE); C=O double bond (like Nylon, PET, PU, PC)
Hydrogen bonds induces polarity and occurs if
C-OH single bond (like PU-polyurethane); N-H Single bond (Like PU, Nylon)

Formation of Polymers
Addition (or Chain-Growth) Polymerization
Most Commodity (cheap) plastics
Instantaneously, the polymer chain forms with no by-products
Chain-reaction mechanism that proceeds by several sequential steps as shown in Figure 2.20. Polymerization begins at one location on the monomer by an initiator
Condensation (or Step-wise) Polymerization
Most Engineering plastics (pellets of Nylon, PC, PET, Polyurethane)and themosets (liquids of epoxy, polyester, polyurethane)
Step-growth polymerization proceeds by several steps which result in by-products.
Monomers combine to form blocks 2 units long
2 unit blocks form 4, which intern form 8 and son on until the process is terminated.
Results in by-products (CO 2 , H 2 O, Acetic acid, HCl etc.)

Nylon (or polyamide) and PC
The repeating -CONH- (amide) link
Polymerized with condensation reaction
Nylon 6- Polycaprolactam: [NH(CH 2 ) 5 CO] x
Nylon 6,6- Polyhexamethyleneadipamide:
[NH(CH 2 ) 6 NHCO (CH 2 ) 4 CO] x
Nylon 12- Poly(12-aminododecanoic acid)- [NH(CH 2 ) 11 CO] x
Polycarbonates are linear, amorphous polyesters because they contain esters of carbonic acid and an aromatic bisphenol (C 6 H 5 OH)
Polymerized with condensation reaction
O C CH 2 CH 2 C O O n

Homopolymers
Plastics Involving Three+ Substitutions (use Table 3.2)
e.g. PTFE polytetrafluoroethylene (Teflon) C C W X Z Y n C C F F F F n

Copolymers and Ter Polymers
Plastics Involving Two mers in chain or 3 mers (ABS)
e.g. SAN styrene acronitrile
Structure of two mers can be OR the same three mers with a C
Alternating- ABABABABABABAB
Random copolymer- AABBABBBAABABBBAB
Block copolymer- AABBBAABBBAABBBAABBB
Graft copolymer- AAAAAAAAAAAAAAAAAAAAAAAAAA
B B B
B B B
B B B
C C H H H n C C H C:::N H H m

Thermosets
Thermosets are polymers that undergo a chemical reaction during the polymerization.
Thermosetting reaction is not reversible under heat.
Epoxy
Standard epoxy is based on bisphenol A and epichlorohydrin.
Properties include good adhesion to many substrates, low shrinkage, high electrical resistivity, good corrosion resistance, and thermal.
Processing is achieved without generation of volatiles.

Polyester and Polyurethane
Polyester
Thermoset reaction between a difunctional acid (or anhydride) and a difunctional alcohol (glycol)
Heat or radiation can trigger the cross linking reaction
Accelerators (or promoters) speed up the reaction.
Condensation Reaction results in CO 2 and H 2 O.
Monomer required to polymerize, e.g., Styrene at 30% to 50% in commercial polyester systems
Polurethane
Reaction between isocyanate and alcohol (polyol). Condensation Reaction results in CO 2 and H 2 O.
Crosslinking occurs between isocyanate groups (-NCO) and the polyol’s hydroxyl end-groups (-OH)
Thermoplastic PU (TPU) have some crosslinking, but purely by physical means. These bonds can be broken reversibly by raising the material’s temperature, as in molding or extrusion.

Thermoplastic Elastomers, Natural Rubber
Thermoplastic Elastomers result from copolymerization of two or more monomers.
One monomer is used to provide the hard, crystalline features, whereas the other monomer produces the soft, amorphous features.
Combined these form a thermoplastic material that exhibits properties similar to the hard, vulcanized elastomers.
Thermoplastic Urethanes (TPU) were the first Thermoplastic Elastomer (TPE) used for seals gaskets, etc.
Other TPEs
Copolyester for hydraulic hoses, couplings, and cable insulation.
Styrene copolymers are less expensive than TPU with lower strength
Styrene-butadiene (SBR) for medical products, tubing, packaging, etc.
Olefins (TPO) for tubing, seals, gaskets, electrical, and automotive.
Natural Rubber is an elastomer that comes from rubber trees in Asia
Properties are increased by vulcanization with sulfur to make it strong.
Automobile tires use a large amount of Natural rubber and SBR

Plastics Questions
A bond between 2 carbon atoms is a _______ bond.
A CH3 groups is called a __________ group.
A dash between atoms indicates a ______ bond.
The small repeating units that make up a plastic molecule are called ___________
What does poly mean? ___________
3 types of intermolecular forces found in plastics are ___________ , ____________, and ____________.
What type of bonding makes Nylon 6 stronger than nylon 12? _____________
Crystalline plastics are more rigid and not as transparent as _________ plastics.
A _______ material may be softened repeatedly when heated and hardened when cooled.
The term used to describe tying together adjacent polymer chains is _______
If the different mers make up the composition of a polymer , it is called a ______.
A Hydrogen molecule which contains some double bonds is called ________.
Is PVC a copolymer? _________ Explain- _____________________________.
What is the general structure of an alternating copolymer? __________________.
If a carbon chain has a methyl side group, is it branched? _________ Explain- _____________________________.
If a material is transparent, is it crystalline? ____________
What effect do dipoles and hydrogen bonds have on melting point of polymers ___________
Is residual stress synonymous with orientation? ____________________
How does the tensile strength and melting point change with increasing crystallization? ______

Processing of Polymers
Thermoplastics
injection molding, extrusion, blow molding, thermoforming, rotational molding, compression molding
Usually uses high pressure processes and imparts high residual stresses on the material which an cause warping in part.
Thermosets
compression molding, reaction injection molding, resin transfer molding, casting, hand layup, etc.
Elastomers
compression molding, extrusion, injection molding, casting.

Injection Molding Process and Cycle Time

Extruder Equipment
Exit zone- die
die imparts shape on the material, e.g., rod, tube, sheet, channel
exit material is called extrudate
extrudate swells at end of die due to normal forces from the polymer flow, called die swell
Cooling zone
water bath or air cooled to lower the temperature below Tg
Auxiliary equipment
puller
rollers for proper thickness
Wind-up or cut off
Die Swell

Compression Molding Process
Materials
Thermosets: Polyester, Vinyl ester, or Epoxy resins with glass fiber
Sheet Molding Compound (SMC), Bulk Molding Compound (BMC)
Thermoplastics: Polypropylene, polyester, or others with glass fibers
Glass Mat Thermoplastic (GMT), thermoplastic BMC
Elastomers: Thermoplastic or Thermoset rubbers
Thermoplastic Olefin (TPO), Thermoplastic Elastomer (TPE), Thermoplastic Rubber (TPR)
Thermoset Styrene Butidiene Rubber
Thermoplastic: Heat Plastic prior to molding Thermosets: Heat Mold during molding

Resin Transfer Molding Process Ref: MSU Tutorial- http://islnotes.cps.msu.edu/trp/liquid/rtm/
Materials
Thermosets: Polyester, Vinyl ester, or Epoxy resins with glass fiber

Polyurethane Processing
Polyurethane can be processed by
Casting, painting, foaming
Reaction Injection Molding (RIM)

Thermoset Reacting Polymers
Process Window
Temperature and pressure must be set to produce chemical reaction without excess flash (too low a viscosity), short shot (too high a viscosity), degradation (too much heat)

Compression Molding
Compression molding was specifically developed for replacement of metal components with composite parts. The molding process can be carried out with either thermosets or thermoplastics. However, most applications today use thermoset polymers. In fact,compression molding is the most common method of processing thermosets.

Resin Transfer Molding
In the RTM process, dry (i.e.,unimpregnated ) reinforcement is pre-shaped and oriented into skeleton of the actual part known as the preform which is inserted into a matched die mold.
The heated mold is closed and the liquid resin is injected
The part is cured in mold.
The mold is opened and part is removed from mold.

Injection Molding Glass Reinforced Composites
Plastic pellets with glass fibers are melted in screw, injected into a cold mold, and then ejected.
Glass filled resin pellets

Chap 14: Composites
Composite Materials
Composite Construction
Composite Applications
Processing of Composites
Review Questions

Polymers Composites
Objectives
Define the components and difference types of composites.
Explain the different types of composite construction and the reasons behind them.
Describe the various manufacturing methods used to produce composites.
List the different reinforcing materials used in composites.
List the various matrix materials used in composites.
Excellent Web sites
Michigan State http://islnotes.cps.msu.edu/trp/
U of Delaware http://www.ccm.udel.edu/publications/CU/99/
Cornell University http://www.engr.siu.edu/staff2/abrate/NSFATE/links.htm

Composites
Composite definition
A composite is a material comprised of two or more physically distinct materials with at least one material providing reinforcing properties on strength and modulus.
Natural Composites
Bone
Wood
Bamboo: Natures fiber glass due to pronounced fibrillar structure which is very apparent when fractured.
Muscle and other tissue
Engineering Composites
Reinforced concrete beams
Thermoset composites: Thermoset resins (polyurethanes, polesters, epoxies)
Glass fibers, Carbon fibers, Synthetic fibers, metalfibers, or ceramic fibers
Thermoplastic composites (polypropylene, nylon, polyester,TPU,polyimide)
Glass fibers, Carbon fibers, Synthetic fibers, metalfibers, or ceramic fibers

Composite Classifications
Reinforcement Type
Discontinuous (fibers are chopped and dispersed in matrix resin)
Short fibers: fiber lengths 3mm or less (most injection molded materials)
Long fibers: fiber lengths greater than 6 mm. (Some injection molded materials with 6mm fibers, Sheet Molding Compound (SMC) with 1” fibers, DFP Directed Fiber Preforms for RTM and SRIM)
Particulates: fibers is forms as spheres, plates, ellipsoids (some injection molded materials reinforced with mineral fibers)
Continuous (fibers are throughout structure with no break points)
Glass roving: glass bundles are wound up in a packet similar to yarn.
Roving is woven into several weaves using a loom machine like in apparel.
Mat products: random swirl glass pattern.
Woven product: roving is woven into machine direction (warp) and cross direction (weft)
Uni product: roving is woven in one direction with a cross thread given to hold mat together.

Glass Fiber Applications
Discontinuous (Chopped) Fiber
Short fiber (L= 3mm) reinforcement for thermoplastic materials that are injection molded (PP and Nylon)
Long Fiber (L=6mm) reinforcement for thermoplastic materials that are injection molded (Nylon)
Chopped Fiber (L=12 mm to 25 mm) reinforcement for thermoset (SMC and BMC) and thermoplastic BMC that are compression molded into parts for Corvette hoods and doors, bumpers, Ford Truck box, and consumer box shapes
Continuous (Mat) Fiber
Many types of weaves for automotive or aerospace applications
Automotive: Viper hood with RTM, GM Truck box with SRIM, Corvette floor pan with RTM
Aerospace: Prepregs, Wings, Fuselages with RTM and SCRIMP

Carbon/Graphite Fibers
Need for reinforcement fibers with strength and modulii higher than those of glass fibers has led to development of carbon
Thomas Edison used carbon fibers as a filament for electric light bulb
High modulus carbon fibers first used in the 1950s
Carbon and graphite are based on layered structures of hexagonal rings of carbon
Graphite fibers are carbon fibers that
Have been heat treated to above 3000°F that causes 3 dimensional ordering of the atoms and
Have carbon contents GREATER than 99%
Have tensile modulus of 344 Gpa (50Mpsi)

Need for reinforcement fibers with strength and modulii higher than those of glass fibers has led to development of carbon
Thomas Edison used carbon fibers as a filament for electric light bulb
High modulus carbon fibers first used in the 1950s
Carbon and graphite are based on layered structures of hexagonal rings of carbon
Graphite fibers are carbon fibers that
Have been heat treated to above 3000°F that causes 3 dimensional ordering of the atoms and
Have carbon contents GREATER than 99%
Have tensile modulus of 344 GPa (50Mpsi)

Manufacturing Process
Current preferred methods of producing carbon fibers are from polyacrylonitrile (PAN), rayon (regenerated cellulose), and pitch.
PAN
Have good properties with a low cost for the standard modulus carbon
High modulus carbon is higher in cost because high temperatures required
PITCH
Lower in cost than PAN fibers but can not reach properties of PAN
Some Pitch based fibers have ultra high modulus (725 GPa versus 350GPa) but low strength and high cost (Table 3-2)

PAN Manufacturing Process Figures 3-3 and 3-4
Polyacrylonitrile (PAN) is commercially available textile fiber and is a ready made starting material for PAN-based carbon fibers
Stabilized by thermosetting (crosslinking) so that the polymers do not melt in subsequent processing steps. PAN fibers are stretched as well
Carbonize: Fibers are pyrolyzed until transformed into all-carbon
Heated fibers 1800°F yields PAN fibers at 94% carbon and 6% nitrogen
Heated to 2300°F to remove nitrogen yields carbon at 99.7% Carbon
Graphitize: Carried out at temperatures greater than 3200° F to
Improve tensile modulus by improving crystalline structure and three dimensional nature of the structure.
Fibers are surface treated
Sizing agent is applied
Finish is applied
Coupling agent is applied
Fibers are wound up for shipment

PITCH Manufacturing Process
Pitch must be converted into a suitable fiber from petroleum tar
Pitch is converted to a fiber by going through a meso-phase where the polymer chains are somewhat oriented though is a liquid state (liquid crystal phase)
Orientation is responsible for the ease of consolidation of pitch into carbon
Stabilized by thermosetting (crosslinking) so that the polymers do not melt in subsequent processing steps
Carbonize: Fibers are pyrolyzed until transformed into all-carbon
Heated fibers 1800°F
Heated to 2300°F
Graphitize: Carried out at temperatures greater than 3200° F to
Improve tensile modulus by improving crystalline structure and three dimensional nature of the structure.
Fibers are surface treated
Sizing agent is applied
Finish is applied
Coupling agent is applied
Fibers are wound up for shipment

Carbon Fiber Mechanical Properties
Table 3-2 (from MFGT 104)

Composites Have a Fiber Preform
Fiber type
Roving form that can be sprayed into a 3-D preform
Roving form that is woven into a glass sheet and then formed to shape (preform)

Sheet Molding Compound (SMC)
SMC is the paste that is compression molded
33% polyester resin and stryrene, which polymerizes and crosslinks
33% glass fibers (1” fibers)
33% Calcium Carbonate

Open Mold processes
Vacuum bag, pressure bag, SCRIMP
autoclave: Apply Vacuum Pressure and Heat in an oven which can be 5 feet to 300 feet long

Structural RIM
Fiber preform is placed into mold.
Polyol and Isocyanate liquids are injected into a closed mold and reacted to form a urethane.

Open Mold processes
Hand lay-up and Spray-up
Filament winding

Composite Classifications
Resin (or matrix) type
Thermoset resins- those that undergo a chemical cross-linking reaction
Epoxy; Polyester; Polyurethane; Phenolic
Silicone; Melamine
Thermoplastic resins- those that are formed under heat
Polyamines (nylon) (short and long fibers)
Polyesters (short and long fibers)
Polypropylene (short, long fibers and continuous fibers)
Other thermoplastic resins (short and long fibers)
Fiber Reinforcements
Glass for reinforced composites with concentrations less than 50% weight
Carbon fiber for Advanced (aerospace) composites with concentrations greater than 60% by weight.
Kevlar fiber for Advanced (aerospace) composites.
Core or Laminate structures
A foam core material can be added (sandwiched) between the layers of resin and fiber.
Composite laminate has a core material with resin and fiber combinations

Processing and Composites Questions
A composite material is a combination of a reinforcing element and ___________.
How are advanced composites are distinguished from reinforced plastics?_________
The fibers in advanced composites are usually made from what? ____________
What two functions does the matrix of a composite serve? ________________
Under what conditions should graphite fibers versus carbon fibers be used? _______

Chap 15: Ceramics
Ceramic Applications
Ceramic Structures
Glass
Advanced Ceramics
Processing of Ceramics
Review Questions

Introduction
Ceramics are
complex compounds and solutions that contain both metallic and nonmetallic elements,
heated at least to incandescence during processing applications,
typically hard and brittle,
exhibit high strength and high melting points,
exhibit low thermal and electrical conductivity.
Applications
Pottery, brick, tile, glass, ovenware, magnets, refractories (resist high temperature), cutting tools.
Furnace linings and tiles for space shuttle due to high resistance to heat.
Superconductivity applications

Ceramics
Traditional ceramics are made from clay, silica, and feldspar
Structural clays for bricks, sewer pipes, drain tiles, and floor tiles are made from natural clays made from three basic components
Traditional ceramic products are china, dental porcelain, and sanitary-ware
Technical ceramics are mainly pure compounds or nearly pure compounds of primarily oxides, carbides, or nitrides.
Carbides: with Silicon, tungsten, titanium, or tantalum Carbides
Extreme hardness and wear resistance allows Use for cutting tools and abrasives
Nitrides: with Boron, Silicon, or titanium Nitrides
Ti-Nitride used as surface coating for cutting tools is brittle so B-nitride is added
Boron Nitride is called cubic boron nitride (CBN) is used for cutting tools.
Normally hot pressed in dry powder form onto useful products.

Ceramics
Ceramics comes from Greek word keramos , which means potter’s clay .
Ceramics are diverse group of nonmetallic, inorganic solid compounds with a wide variety of compositions and properties.
Ceramics are crystalline compounds made up of metallic and nonmetallic compounds with properties that differ from the constituents.
Ceramics in the form of pottery are among the oldest products manufactured by humans.
Clay is inexpensive material and is found throughout the world.
Early clay products were sun dried not fired.
Firing as used in pottery dates back to around 2000 to 3000 B.C.

Ceramics Properties
Ceramics are crystalline like steel but have few free electrons at room temperature and thus are low conductivity.
Ceramics strengths have higher compressive than tensile.
Ceramics are totally elastic, exhibiting no plasticity when load is applied with little or no deformation prior to fracture.
In general ceramics have the highest melting points of any materials. Range from 3500F to as high as 7000F.
Manufacturing of ceramics involves
blending fine starting materials with water to form mass that is shaped
formation includes extrusion, pressing, and casting,
use of potter’s wheel for cups, bowls, saucers, etc.
extruded to make bar shapes or poured into mold as slip slurry
after forming product is dried to remove water and fired for strength
forming provides fusion ( sintering ) and chemical reaction for bonding
glazing with ceramic coating for smooth surface

Ceramics Materials
Properties
Vary depending on composition, microstructure, and processing.
Excellent resistance to
compressive loads, abrasion, heat, and staining
chemical attacks, weather attacks, bending (excellent rigidity)
Poor resistance to tensile loads, spalling (thermal cracking ceramics)
Most ceramics will crack if thermal cycled, except Pyrex glass which contains boric oxide to provide expansion properties.
Applications
dielectric materials for capacitors with disk capacitors (mainly barium titanate) being the most common.
Semiconductor applications with sintered oxides, e.g., thermistors, which are thermally sensitive resistors used for temperature control
Piezoelectric ceramics (Barium titanate) is used in accelerometers and speakers. The transducers convert input sound energy into electrical response or convert electrical inputs into sound energy.
Nanocomposites for plastics and composites

Glass
Glasses are described as super-cooled liquids.
Glasses do not behave like metals but more like polymers when cooled from molten condition
Metals exhibit a definite quantity of heat given off when cooled and form a crystaline (or regular) structure when cooled.
Heat is called heat of solidification
Polymers exhibit changes in volume when cooled which may form a crystalline or amorphous structure depending upon the nature of the polymer and versus temperature that has an inflection point, know as glass transition temperature.
Glass is a transparent silica product which may form an amorphous or crystalline structure depending upon heat treatment during production.
Glass do not exhibit any indication of transition or a clear point of inflection when cooling from molten state.
Glass is considered a viscous liquid when cooled from molten state.
Glass has the appearance and feel of a solid material but will flow like a liquid given time, e.g., thicker glass at bottom of window pane.
Crystallinity of glasses is measured with X rays and X-ray diffraction.
More crystalline the glass the more rays are diffracted

Glass Manufacturing
Glass blowing process
Glass blowpipe is a hollow iron tube from 4 to 5 ft long with a knob at one end and a mouthpiece at the other end.
Dip knob end into melted glass, where glass sticks to the end of pipe.
Air is blown gently while rotating pipe which produces a hollow bulb of glass, where the thickness of the bulb depends on size of bulb.
The bulb cools and solidifies into a number of symmetrical shapes.
Molds are used to rapidly cool glass and allow more many shapes, including, bottles, dishes, lamps, and jars.
Composition
Glass is made primarily of sand (silicon dioxide)
Silica or quartz glass is pure silicon dioxide (very stable)
Window glass is made of sand (SiO 2 ), limestone (CaCO 3 ), and soda ash (Na 2 Co 3 )

Traditional Ceramic Products Are China, Dental Porcelain, And Sanitary Ware

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