ceramics

Examples of engineering, dielectric, optical ceramics

Engineering: oxide: Al2O3, non oxide: SiC Dielectric : strontium titanate (ST), calcium titanate (CT), magnesium titanate (MT), Optical ceramics: Al2O3, YAG, Nd: YAG, Yttrium oxide (Y2O3)

Examples of ceramics with ionic bonding

MgO, CaO, Al2O3, ZrO2

Examples of ceramics with covalent bonding

SiC, TiC, AlN, Si3N4

Give a basic differences between the monocrystalline oxide compound and ceramics

Monocrystalline oxide is not necessarily sintered, Ceramics are sintered material and we know the way of the uprising

Examples (3) of advanced ceramics

Si3N4, Zr2O3, SiC

Examples (3) of traditional ceramics

faience (quartz+ feldspar), porcelain (kaolin+quartz+feldspar), stoneware (stoneware products are produced from clay raw materials)

Main stages of ceramic technology

Raw materials → Chemical treatment → Milling → Batching → Mixing → Forming → Drying → Sintering → Final machining

What parameters are essential for characterization of the given powder?

particle size (granulometry), particle shape (morhpology), deegre of fragmentation, chemical composition, purity, degree of crystallinity and concentration of defects

How the surface energy of powder could be decreased?

Surface energy can be reduced by adding wetting agents

Difference between an aggregate and an agglomerate

Aggregate - a collection of crystallites of common borders, An agglomerate - a collection of crystallites or aggregates that contact each other pointwise

Difference between an agglomerate and a granule

The agglomerate is a spontaneously formed porous form composed of crystallites or aggregates contacting each other pointwise. Granula is a powder specially formulated in agglomerates with regular shapes, minimized porosity, created under conditions that allow slipping and dense packing.

Types of bonding in granules

Van der Waals or resulting from binder, electrostatic bonding

Types of bonding in agglomerates

Electrostatic or van der Waals, polymer

List examples (3) of natural raw materials for ceramic industry

Clay, Silica, Kaolinite

List the names (2) of natural hydroxides of alumina-silicates

Kaolinite (Al4[Si4O10](OH)8), Illite K0.6-0.85Al2(Si,Al)4O10(OH)2

Give examples (2) of equipment for crushing brittle raw materials

Hammer Crusher,, Jaw Crusher

Give examples (3) of mills used in ceramic industry

Ball mill, Roller mill, Atritor mill

Could you explain a term “calcination”

Calcination is a heat treatment in order to decompose the materials especially carbonate to its oxide state. It’s use only to simple oxides, is a endothermic reaction,

Give an example (1 reaction) of solid state synthesis of mixed oxides

CaO + TiO2 -&rt; CaTiO3 (perovskite, ferroelectric)

Give an example (1 reaction) of carbothermal synthesis of non-oxide ceramic powder

Si + C = SiC (???) Si3N4 + 3C ⇌ 3SiC + 2N2 (???)