08.11.2006claudia eisermann1 earthenware, pottery, porcelain, ceramics - which ingredients are...

08.11.2006 Claudia Eisermann 1

Earthenware, pottery, porcelain, ceramics - which ingredients are

needed to allow molding and what happens during burning ?


Contents:

• Overall view• Pottery• Porcelain• Ceramics• Which ingredients

allow molding ?• Burning


Overall view

• Earthenware: - used for pottery - made from clay - slightly porous after first firing (not vitrified) - glaze before second firing -> waterproof


Overall view

• Porcelain:

- made from mixture of kaolin and petuntse

- differences to stoneware less clear

- pottery, resonant against pushes

- vitrified pottery


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)


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)


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


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


Pottery

• Properties:

- easy to form

- natural warm color

- long durable

- water-resistant

- resistant against frost (high density -> less water taken up -> small expansion)


Pottery

• Use:

- vessels, statues of animals

- oil lamps

- art, decoration, jewelry

- building materials and commercial materials:

tiles, plates for covering, washbasin, vases,

pots


Porcelain

• called “white gold”• noble products are

hard porcelain and Bone China (made with ash of bones; England)

• famous factories: Meißen, Fürstenberg, Frankenthal


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)


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


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)


Porcelain

• Forming by hand:

- compact mass

- pliable • Foundry:

- liquid mixture

- hollow products

(solid edge -> liquid rest decanted)


Porcelain

• Properties: - thick fragments - shell-shaped break - high roughness - constant against acids and lye - bright sound - constant against high temperatures - isolation against electricity


Porcelain

• Use:

- decoration

- isolator

- dishes

- chemical device (crucible)


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)


Ceramics

• Production:

- clay, water

- mixture cast/formed/pressed

- burning (600 °C) -> moisture removed

- 2nd burning -> smooth surface

- decoration (stamp, carving, cut parts out)

- glaze


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


Ceramics

• Use:

- mechanical engineering, process engineering

- electronics

- high temperature technique

- building materials: tiles, plates

- sanitary, appliances in the household (dishes)

- pots


High-performance ceramic

• since 1960• properties depend on use• efficient• example: dental ceramic

- 1st burning: 1100 °C

- 2nd burning: 1700 °C


ingredients

• bigger than product (water evaporate)• chamotte -> little loss• organic additives: deflocculant, binding agent• 1st burning -> additives removed• green body (formed, not burned)


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


Burning

• clay + silicic acid -> Silimanit (Al2O3*SiO2), Mullit (3 Al2O3*2 SiO2)

= double chains of silicate


research/development

• improve specifications • resistant against acid• corrosion protection• electrical isolation

• ceramic industry connected with chemistry


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

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