Ceramics Class

بِسم الله الرَحْمنِ الرَحِيْم

Definition:

This word "Ceramic" was derived from Greek word "Keramikos", which is derived from "Keramon" or "Keramos", meaning "Argil"[1] or pottery.

Another definition is 

Any of various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing a nonmetallic mineral, such as clay, at a high temperature.[2]

But, a ceramic has traditionally been defined as “an inorganic, nonmetallic solid that is prepared from powdered materials, is fabricated into products through the application of heat, and displays such characteristic properties as hardness, strength, low electrical conductivity, and brittleness." 

Structure:

Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous (e.g., a glass). Because most common ceramics are crystalline, the definition of ceramic is often restricted to inorganic crystalline materials, as opposed to the non-crystalline glasses. 

They are most frequently oxide,nitrides, and carbides. For example, some of the common ceramic materials include aluminum oxide (or alumina, Al2O3), silicon dioxide (or silica, SiO2), silicon carbide (SiC), silicon nitride (Si3N4).


Sub-Class:

Ceramic materials can be subdivided into traditional and advanced ceramics. Traditional ceramics are composed of clay minerals (i.e., porcelain), and other natural occuring materials. Clay-base materials such as brick, tile, sanitary ware, dinnerware, clay pipe, and electrical porcelain. Common-usage glass, cement, abrasives, and refractories are also important classes of traditional ceramics.

Advanced ceramics are tailored to have premium properties through application of advanced materials science and technology to control composition and internal structure. Examples of advanced ceramic materials are silicon nitride, silicon carbide, toughened zirconia, zirconia-toughened alumina, aluminum nitride, lead magnesium niobate, lead lanthanum zirconate titanate, silicon-carbide-whisker-reinforced alumina, carbon-fiber-reinforced glass ceramic, silicon-carbide-fiber-reinforced silicon carbide, and high-temperature superconductors. 

Properties : 

Ceramic materials are relatively stiff and strong in compression comparable to those of the metals and weak in shearing an tension. In addition, ceramics are typically very hard. On the other hand, they are extremely brittle (lack ductility), and are highly susceptible to fracture. These materials are typically insulative to the passage of heat and electricity (i.e., have low electrical conductivities, ), and are more resistant to high temperatures and harsh environments than metals and polymers.  With regard to optical characteristics, ceramics may be transparent, translucent, or opaque and some of the oxide ceramics (e.g., Fe3O4) exhibit magnetic behavior.

Atomic Bonding:
 

The atoms in ceramic materials are held together by a chemical bond  Briefly though, the two most common chemical bonds for ceramic materials are covalent and ionic. Covalent and ionic bonds are much stronger than in metallic bonds and, generally speaking, this is why ceramics are brittle and metals are ductile.
  
Footnote: 
1.http://www.caroun.com/Ceramic/General/Definition/Ceramic-1General.htm 
2.http://www.answers.com/topic/ceramics

Picture:
1.http://claygeek.files.wordpress.com/2007/08/ceramic13.jpg

References:
1.http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Introduction/ceramics.htm

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Classification of Materials

In this section we will discuss about the classification of materials. Before entering into the subject I wanted to ask the readers? what the definition of material? and what do you know about the material? this is very important for the answer before sharing materials.

Okay, because our discussion of metallurgy and materials engineering is only natural that we define what we mean material are :

Materials are everywhere around us – make up our world--

The substance or substances out of which a thing is or can be made [1]


Things needed for doing or making something [2]

For those who want to add definition of material please comment below and please include the source or the reference

Now go into the main subject discussion, at the classified material by the following experts in view of the nature (properties). Material divided in six separated major classes of materials: metals, polymers, ceramic, composite, semiconductor, alloy. All of them have different characteristics. Table below can help show the difference that the six classes of material:

Solid materials have been conveniently grouped into three basic classifications based primarily on chemical makeup and the atomic bonding forces of a particular material, and most materials fall into one distinct grouping or another, although there are some intermediates.

These three classifications are metallic, ceramic and polymeric.

In addition, there are the composites, combination of two or more of the above three basic material classes. Another classification is advanced materials—those used in high-technology applications— . semiconductors, biomaterials, smart materials, and nanoengineered materials.

Within each of these classifications, materials are often further organized into groups based on their chemical composition or certain physical or mechanical properties. But we will not discuss it now.

Below is a list of some of the commonly classification of materials within these four general groups of materials.

Metals Ferrous metals and alloys (irons, carbon steels, alloy steels, stainless steels, tool and die steels) Nonferrous metals and alloys (aluminum, copper, magnesium, nickel, titanium, precious metals, refractory metals, superalloys)	Polymeric Thermoplastics plastics Thermoset plastics Elastomers
Ceramics Glasses Glass ceramics Graphite Diamond	Composites Reinforced plastics Metal-matrix composites Ceramic-matrix composites Sandwich structures Concrete

Insya Allah, next post we will discuss the outline of each class of material on top.

Fotenote:

1. http://www.thefreedictionary.com/material
2. http://www.wordreference.com/definition/material

Reference:
http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Introduction/classifications.htm