CERAMICS AND ITS PROPERTIES ACIERTO, BELINO, BETER, BOBIER, CLAMAR, CONTRERAS
INTRODUCTION The term ceramic comes from the Greek word keramikos , which means “ burnt stuf ”. This indicates that desirable properties of these materials are normally achieved through a high-temperature heat treatment process called firing .
HISTORY In 24000 BC, archaeologists found uncovered human-made ceramics in the form of animal and human figurines, slabs, and balls in Czechoslovakia .
HISTORY In 8000 BC, Glass was believed to be discovered in Egypt when overheating of kilns produced a colored glaze on the pottery.
HISTORY In the second half of the 19th century, when ceramic materials for electrical insulation were developed.
CERAMICS Ceramics are inorganic crystalline materials compounded by either a metal and non-metal, or a combination of at least two nonmetallic elemental solids hardened by heating to high temperature.
CRYSTAL STRUCTURES IN CERAMICS Ceramics possess these types of crystal structures according to the amount of Cations and Anions : • AX Type • Type • Type where: A – Cations, X – Anions •
AX TYPE CRYSTAL STRUCTURE This is a type of crystal structure in which the number of cations and the number of anions are equal . Types of crystal structures for AX Compounds: • Rock Salt structure • Cesium Chloride structure • Zinc Blende structure
AX TYPE CRYSTAL STRUCTURE ROCK SALT STRUCTURE The crystal structure of Sodium Chloride (NaCl) CESIUM CHLORIDE STRUCTURE Note: This is not a BCC structure due to the involvement of two different kinds of ions. The unit cell of Cesium Chloride (CsCl)
AX TYPE CRYSTAL STRUCTURE ZINC BLENDE STRUCTURE The unit cell of Zinc Sulfide (ZnS). Zinc Blende is the mineralogical term for ZnS.
TYPE CRYSTAL STRUCTURE A compound can exist with the chemical formula if the charges on the cations and anions are not the same . Note: m – subscript of cation A p – subscript of anion X • The crystal structure of Calcium Fluorite (Ca).
TYPE CRYSTAL STRUCTURE These are ceramic compounds that have more than one type of cation ; for two types of cations (represented by A and B). where: B – Second cation n – subscript of cation B The unit cell of perovskite.
SILICATE CERAMICS Silicates are materials composed primarily of silicon and oxygen , the two most abundant elements in the earth’s crust. Quartz Feldspar Pyroxene
SILICATE CERAMICS Silica or Silicon dioxide (Si) is the most simple silicate material. It is a colorless white chemical compound. • Some uses of silica are absorbing moisture, keeping things dry, filler for paints, and water filtration.
SILICATE CERAMICS Vitreous Silica or Fused Silica is a kind of silica that has a characteristic of a liquid that made to exist as a non-crystalline solid or glass having a high degree of atomic randomness .
- Fall '19
- Materials Science, Ion, Crystal, Silicate Ceramics