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CLASSIFICATION OF CERAMIC MATERIALS.pptx
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- 2. Classification of Ceramicsmaterials Ceramics Materials Traditional ceramics Advanced Ceramics Red clay product Cements Refractorie s White clay product ( whiteware ) Abrasives Glasses
- 3. Traditional Ceramics ♦ Made fromnaturally occurring minerals (three basic components): clay, silica (flint), and feldspar . ■ The clay refers to a naturally occurring material composed primarily of fine-grained minerals, which is generally plastic at appropriate water contents and will harden when dried or fired . ■ The silica SiO2 has a high melting temperature and is the refractory component of traditional ceramics .
- 4. Traditional Ceramics ■ Feldspar (KAlSi3O8– NaAlSi3O8 – CaAl2Si2O8) the most abundant group of minerals in the earth, forming about 60% of the earth's crust, has a low melting temperature and makes a glass when the ceramic mix is fired. acts as flux, lowering the glass batch melting temperature and thus reducing production costs .
- 5. Red-clay product ♦ Made ofnatural clay, which contains all three basic components. It characterized by the red color due to the existence of Fe2O3 Example : • Stoneware It is a type of clay that has been fired at extremely high heat to produce durable material that is capable of withstanding day-to-day use. Numerous types of dishes, mugs, platters and plates are made of it, mostly due to its strength . • Earthenware It is a type of clay that has been fired at low heat between 1,000 and 1,150 °C, has lower mechanical strength . • Building brisk • Tile
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- 7. White-clay product ♦ Made fromcomponents of clay, silica, and feldspar for which the composition is controlled. It characterized by the white color due to the existence of kaolin (china clay) Al2Si2O5(OH)4 . Example : • Porcelain Is a ceramic material generally including kaolin , made by heating materials, in a kiln to temperatures between 1,200 and 1,400 °C. •Dinner china • Sanitary ware
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- 11. Refrecteries ♦ A refractory materialis one that can retain its strength at high temperatures and harsh environment . ♦ They are used in linings for furnaces, incinerators and reactors . ♦ The oxides of aluminium (Tm=2050°C), silicon and magnesium are the most important materials used in the manufacturing of refractories .
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- 14. Cement ♦ Is a binder,a substance that sets and hardens independently, and can bind other materials together . ♦ The most important uses of cement are as an ingredient in the production of concrete, a combination of cement and an aggregate to form a strong building material .
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- 17. Abrasives ♦ Is a material,often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away .
- 18. Glass ♦ As a stateof matter, the term refers to an amorphous (noncrystalline) structure of a solid material . • The glassy state occurs in a material when insufficient time is allowed during cooling from the molten state to the solid state . ♦ As a type of ceramic, glass is an inorganic, nonmetallic compound (or mixture of compounds) that cools to
- 19. ♦ Because Silica SiO2is the best glass former . • Silica is the main component in glass products, usually comprising 50% to 75% of total chemistry . • It naturally transforms into a glassy state upon cooling from the liquid, whereas most ceramics crystallize upon solidification .
- 20. Types of Glass Threecommon types of glass : • Soda-lime glass - 95% of all glass, windows containers etc . • Lead glass - contains lead oxide to improve refractive index .
- 21. Types of Glass Soda-lime-silicaglass, window glass : ♦ Silica 72% + sodium oxide (Na2O) 14.2% + magnesia (MgO) 2.5% + lime (CaO) 10.0% + alumina (Al2O3) 0.6%. Is transparent, easily formed and most suitable for window glass . ♦ It has a high thermal expansion and poor resistance to heat (500–600 °C) . ♦ Used for flat glass, containers, and lighting products where high chemical durability and heat resistant are not needed .
- 22. Types of Glass Lead-oxideglass, crystal glass ♦ Silica 59% + soda (Na2O) 2.0% + lead oxide (PbO) 25% + potassium oxide (K2O) 12% + alumina 0.4% + zinc oxide (ZnO) 1.5% . ♦ Has a high refractive index, making the look of glassware more brilliant (crystal glass). It is also more workable, but cannot stand heating very well .
- 23. Types of Glass Sodiumborosilicate glass, Pyrex ♦ Silica 81% + boric oxide (B2O3) 12% + soda (Na2O) 4.5% + alumina (Al2O3) 2.0%. Stands heat expansion much better than window glass. Used for chemical glassware, cooking glass, car head lamps, etc. Borosilicate glasses (e.g. Pyrex) have as main constituents silica and boron oxide .
- 24. Types of Glass ♦ Theyhave fairly low coefficients of thermal expansion compared to typical soda-lime glass making them more dimensionally stable. The lower CTE also makes them less subject to stress caused by thermal expansion, thus less ability for cracking from thermal shock . ♦ They are commonly used for reagent bottles, optical components and household cookware .