PRACTICAL ENGLISH IN CERAMICS Ceramika Ceramics Ceramika specjalna

PRACTICAL ENGLISH IN CERAMICS • • • Ceramika ---- Ceramics Ceramika specjalna – Special ceramics Ceramika ogniotrwała – Refractory materials Szkło - Glass Szkliwa i emalie - Glazes and enamels Szkło-ceramika - Glass - ceramics Materiały wiążące - Binding materials Cienkie warstwy - Coatings Biomateriały - Biomaterials

Programm: Non-metalic inorganic materials 1. Characteristic of ceramic materials – Sintered (classic ceramics) – Melted (glasses and glazes) – Binding (lime, gypsum, cement, mortars binding ) 2. Sintered ceramics – classic and advanced 3. Glasses and glass-ceramics 4. Special glasses and method of their production (sol/gel method) 5. Bioactive glasses and glass-ceramics materials 6. Amorphous coatings on glassy base 7. Binding materials

CREDIT CONDITIONS OF COURSE • Presence in lectures • Preparation of the seminar paper References to the subject: • Draft of lectures • „Applied Ceramic Technology” vol. I and II; SACMI

My motto • Not the most important presence at lectures!!!! • Most important is - something to understand, learn, remember !!!

What does „ceramics” mean? ? ? Ceramics derives from Greek word Keramos; this is the product formed by the action of fire (sintering) Now (unambiguous definition : Non-metalic, inorganic products obtained by the transformation of mineral or chemical raw materials during high-temperature process

How can we divide ceramics? • SINTERED PRODUCTS (classic ceramics) • MELTED PRODUCTS (glasses) • BINDING MATERIALS (lime, gypsum, cement)

SINTERED MATERIALS Examples: • Porcelain tableware • Building ceramics – brick, slate, various tiles: floor and wall • Sanitary ware • Advanced ceramics

SINTERED MATERIALS Kind of tiles: Floor and wall Wall tiles: double and single fired; • Classification on the base of forming method • Technical features: porosity between 13 -18% • Glazes are usually used Floor tiles: • Vitrified single fired tiles („gres”)-compact mass • Porcelain tiles, usually glazed

MELTED MATERIALS (GLASSES) • Soda-lima-silica glasses (building, automotive, packaging, tableware) • Optical glasses • Technical glasses • Crystal glasses • Bio-glasses

BINDING MATERIALS • Lime (Ca. O from Ca. CO 3)) • Gypsum (Ca. SO 4) • Cement (cement clinker + gypsum + mineral additions –ashes)

Basic differences between particular groups of materials • These differences concern: - production process -structure, microstructure and material properties -application

DIFFERENCES - PROCESS SINTERED MATERIALS Raw materials preparation Preparation of ceramic body Formation ceramic body Drying and sintering

SINTERED CERAMICS Raw materials: • Plastic: clay minerals - kaolinite Al 4[Si 4 O 10](OH)8 , illite Al 2(Si 5 O 10)(OH)2 montmorillonite; • Non-plastic: silica Si. O 2 (to do smaller body contraction) , feldspars X 4(Al 4 Si 4 O 16) X – K, Na (fluxing agents)

Kaolinite structure • Basic element of kaolinite: • - silica-oxygen sheet („tetrahedral sheet”) • - alumina-oxygen-hydroxyl sheet („octahedral sheet”) ------------------------------ • L. K. Si = 4______________ [Si. O 2 O 5 ]-2 • ______________ H 2 O • L. K. Al = 6______________ [Al. O 6]-9

Kaolinite spatial structure

DIFFERENCES - PROCESS MELTED PRODUCTS (GLASSES) Raw materias preparation Melting Forming from the melt Vitrification

GLASSES Raw materials: • Glass-forming compounds (high viscosity at melting temperature): Si. O 2; B 2 O 3, P 2 O 5; • Fluxing agents: carbonates of alkaline element – Na 2 CO 3; K 2 CO 3; Li 2 CO 3 • Modifieres – Pb. O, Ba. O, Zn. O

BINDING MATERIALS èMaterials in the form of powders; èLack of product formation; è They are able to bind after water addition

BINDING MATERIALS Raw materials: Limestone, marl, clays clinker Clinker compounds: silicates and aluminates

DIFFERENCES: STRUCTURE AND PROPERTIES Ceramics: Poly-crystalline products; can contain amorphous phase; produced from mineral raw materials by firing; products are not-translucent or translucent (porcelain) Glasses: amorphous products; no long-range ordering of structure; products are transparent Binding materials: poly-crystalline products in the form of powders

CERAMIC PRODUCT CLASIFICATION • Criteria: - Physical features (colour, porous structure, optical properties) - Production technology ( method of formation; double or single firing; use or not glazes) - Application

CERAMIC PRODUCT CLASIFICATION Physical features Porosity: Compact or porous structure (porosity 312%) – dependent on formation method and firing temperature) Color: White or red after firing (dependent on the content of iron in raw materials)

Porous products Coloured (red) after firing White after firing Øbrick Øfaience Ø refractory ØSome products of advanced ceramics Øpottery

NON-POROUS PRODUCTS Not-translucent: • Stoneware; • Semi-vitreous Translucent, white • Porceain Low-translucent products (yellow) • Steatite products • Advanced products for the electronic

CERAMIC PRODUCT CLASIFICATION Production technology Formation: • castings, • plastic extrusion • pressing

PRODUCTION PROCESS SINTERED MATERIALS Raw materials preparation Preparation of ceramic body Formation from ceramic body Drying and sintering

SINTERED CERAMICS Raw materials: • Plastic: clay minerals - kaolinite Al 4[Si 4 O 10](OH)8 , illite Al 2(Si 5 O 10)(OH)2 montmorillonite; • Non-plastic: silica Si. O 2 (to do smaller body contraction -shrinkage) , feldspars X 4(Al 4 Si 4 O 16) X – K, Na (fluxing agents) • Helpful raw materials

Plastic raw materials v. Clays (illite-chlorite, illite-kaolinitic types) v. Kaolins v. Bentonites v. Shale rocks • Mineralogical characterisation: sedimentary rocks composed of various types of silicate minerals, mostly hydrarted aluminum silicates (Al 2 O 3 m. Si. O 2 n. H 2 O).

Plastic raw materials • Basic feature of clays: PLASTICITY– ability, after introducing of water, formation of mass, which can be shaped by various methods, and obtained shape is preserved during and after drying and firing

COMPLEMENTARY RAW MATERIAL Role in production process - to reduce shrinkage during drying and firing of plastic raw materials • Silica raw materials(Si. O 2): Quartz, qartzites, quartz sands • Raw materials of high content of alumina Al 2 O 3 v. Aluminum raw materials: alumina, aluminum hydroxides; valuminum, synthetic materials (corundum); v. Aluminum-silicate raw materials: : sillimanite,

COMPLEMENTARY RAW MATERIAL Role in production process Fluxes; decreasing sintering and melting temperatures! • Feldspars: v Potasium feldspar (ortoklaz) K 2 O Al 2 O 3 Si. O 2; v Sodium feldspar (albit) Na 2 O Al 2 O 3 Si. O 2; v Calcium feldspar (anortyt) Ca. O Al 2 O 3 Si. O 2 • Carbonates of calcium and magnezium (Ca, Mg): v Calcium carbonate. Ca. CO 3; v Magnesium carbonate Mg. CO 3; v Double calcium/magnesium carbonate Ca. CO 3 Mg. CO 3;

Clays classification as the raw materials for ceramics production: • Content of impurities in the form of iron compounds (it affects on the product color after firing • Content of impurities in the form of calcium, magnesium, potasium, sodium compounds playing the role of fluxing agents (this determines the fire resistance)

Examples: • Kaolin and clays (ball clays, china clays) – firing in white or cream (low content of iron compounds) they are used to porcelain and faience production • Clays for brick production (marl-carbonate clay, vitrifiable clay); after firing they take on beige-orange color due to present of ferrous minerals; • Refractory clays (Kaolin-type chinaclays) , low content of fluxing agents (less than 6%), give a product with a high fire resistance

Sintered products • Raw materials preparation • Preparation of ceramic body • Shaping of ceramic body (ambient conditions) • Drying and sintering (firing) – hightemperature process

Raw materials and ceramic body preparation Raw materials preparation: • Enrichment (removal of not-profitable components) • Pre-processing - (crushing) Compilation of ceramic body; Examples: faience: clays: medium-plastic very plastic 30% 32% marble or chalk (Ca. CO 3) 12% quartz sands 26% porcelain Clays – kaolin type (Ball-clays, china clays) Feldspar Quartz 50% 25%

Body compilation- wall tiles

Ceramic body preparation Removal of water and air from mass using special filter or vacuum press Vacuum press

Ceramic body fate What is the fate of body ? content of H 2 O in % v. Casting 25 -35 v. Plastic extrusion 15 -25 v. Plastic pressing 10 -14 v. Dry pressing 3 -9

Shaping of body èCasting in gypsum form èFormation from plastic mass –hand made, extrusion, formation on press èPressing v. Dry and semi-dry mass v. Plastic mass v. Thermo-plastic formation

Casting in gypsum form Preparation of slip body - water suspension of ground raw ceramic – low viscosity, low sedimentation rate, low shrinkage (addition of fluidization agents : sodium silicates – „water” glass)

Casting of slip body in gypsum form Body is left in gypsum form up to body densification (water is removed from body by gypsum form absorption)

Plastic body formation Hand made: • Various type of clay body modeling Turning of ceramics: The oldest way of formation: – potter's wheel