08.11.2006claudia eisermann1 earthenware, pottery, porcelain, ceramics - which ingredients are...
TRANSCRIPT
08.11.2006 Claudia Eisermann 1
Earthenware, pottery, porcelain, ceramics - which ingredients are
needed to allow molding and what happens during burning ?
08.11.2006 Claudia Eisermann 2
Contents:
• Overall view• Pottery• Porcelain• Ceramics• Which ingredients
allow molding ?• Burning
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Overall view
• Earthenware: - used for pottery - made from clay - slightly porous after first firing (not vitrified) - glaze before second firing -> waterproof
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Overall view
• Porcelain:
- made from mixture of kaolin and petuntse
- differences to stoneware less clear
- pottery, resonant against pushes
- vitrified pottery
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Overall view
• Ceramics:
- differences to porcelain in roughness and stability
- important material: clay
- depending on use high quality claim
- able to produce wanted color (porcelain too)
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Pottery• History: - before Christ: vessel - 15th century: decoration; first
mould - 18th century: moulds of plaster - 19th century: mechanization
(England)• Important ages: - ancient world, renaissance
(Donatello, Luca della Robbia)
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Pottery
• Production: - red clay (Fe) or yellow clay (lime) - clay dug out, dried, ground - water added, mixed 1) moulds: equal layer -> plaster takes water ->
pottery shrinks -> precision work 2) handwork: forming with hands, wet cloth,
wooden spatula, slow drying before burning
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Pottery
• Burning: - dry products (water evaporates ->cracks) - 1000°C, 5 – 10 days - slow cool down - to high temperature -> vitrification - to low temperature -> porous - pottery in cool water -> lime extinguished ->
pores density increases
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Pottery
• Properties:
- easy to form
- natural warm color
- long durable
- water-resistant
- resistant against frost (high density -> less water taken up -> small expansion)
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Pottery
• Use:
- vessels, statues of animals
- oil lamps
- art, decoration, jewelry
- building materials and commercial materials:
tiles, plates for covering, washbasin, vases,
pots
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Porcelain
• called “white gold”• noble products are
hard porcelain and Bone China (made with ash of bones; England)
• famous factories: Meißen, Fürstenberg, Frankenthal
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Porcelain
• History:
- developed in year 620 in China
- 1708 in Europe, by Ehrenfried Walther von Tschirnhaus
- continued by Johann Friedrich Böttger
- 1710, Meißen: first manufacture in Europe
(which became famous in the world)
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Porcelain
• Hard porcelain:
- Kaolin (50%), feldspar (25%), quartz (25%)
- third burning temperature: 1410 °C
• Soft porcelain:
- Kaolin (40%), feldspar (30%), quartz (30%)
- third burning temperature: 1300 °C
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Porcelain• Production: - mixture of 3 materials - forming by hand (spinning slice) or by machines (pressure) - first firing (850 – 950 °C), cool down (slow) - second firing (1300 – 1410 °C) - glaze applied - painting + glaze - third firing (780 – 1410 °C, depending on glaze)
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Porcelain
• Forming by hand:
- compact mass
- pliable • Foundry:
- liquid mixture
- hollow products
(solid edge -> liquid rest decanted)
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Porcelain
• Properties: - thick fragments - shell-shaped break - high roughness - constant against acids and lye - bright sound - constant against high temperatures - isolation against electricity
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Porcelain
• Use:
- decoration
- isolator
- dishes
- chemical device (crucible)
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Ceramics• History:
- before Christ: rotating potter´s wheel in China
- 16th century: fly wheel
- 19th century: pedal -> two free hands
- 20th century: electric motor (regular speed)
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Ceramics
• Production:
- clay, water
- mixture cast/formed/pressed
- burning (600 °C) -> moisture removed
- 2nd burning -> smooth surface
- decoration (stamp, carving, cut parts out)
- glaze
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Ceramics
• Properties:
- high roughness
- resistant against weather
- bears high temperatures
- electrical isolation
- very low wear
- dimensional stability
- adapted to the use (raw materials, production)
- different colors
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Ceramics
• Use:
- mechanical engineering, process engineering
- electronics
- high temperature technique
- building materials: tiles, plates
- sanitary, appliances in the household (dishes)
- pots
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High-performance ceramic
• since 1960• properties depend on use• efficient• example: dental ceramic
- 1st burning: 1100 °C
- 2nd burning: 1700 °C
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ingredients
• bigger than product (water evaporate)• chamotte -> little loss• organic additives: deflocculant, binding agent• 1st burning -> additives removed• green body (formed, not burned)
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Burning
• raw material compacted, less porous
• adapted temperature, pressure, time
• carbon built in the material
-> stable• coking (about 1000 °C)
-> organic additives turn to carbon
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Burning
• clay + silicic acid -> Silimanit (Al2O3*SiO2), Mullit (3 Al2O3*2 SiO2)
= double chains of silicate
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research/development
• improve specifications • resistant against acid• corrosion protection• electrical isolation
• ceramic industry connected with chemistry
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sources• Hollemann, Wiberg; Lehrbuch der anorganischen Chemie, de Gruyter, 1985
• http://de.wikipedia.org/wiki/Porzellan
• http://de.wikipedia.org/wiki/Keramik
• http://www.frankreich-sued.de/Limoges/Porzelan.htm
• http://www.toepferhof-online.de/Ofen/ofennabe.html
• http://www.uni-protokolle.de/Lexikon/Porzellan.html
• http://www.uni-saarland.de/fak8/powdertech/projekte/projekt_oetzel_client.html
• http://www.unileoben.ac.at/~buero41/daabs/winter.htm
• http://www.komage.de/zahnkeramik.php
• http://www.crystec.com/kllcerad.htm
• http://www.fbi-biomaterialien.de/ima/weblication/deutsch/mains/2_charakterisierung.htm
• http://www.fz-juelich.de/zb/text/publikation/juel3227.html