Engineering materials and engineering materials properties, Physics

Engineers and technologist engage themselves in the design and manufacturing of machine like latches, engines, motors, generators, bulldozers etc. And in the fabrication of vehicles like aircraft, trains, automobiles. When we analyze the products of engineering industry for their constituent materials, we find that the materials that are primarily used are solids, fluids like water, oil and steam. But solid with their properties manipulated with the variety of ways dominate the industry. Solid materials may be conveniently grouped into four different groups. It is possible to be conversant with the thousands of engineering materials, unless we are guided by some broad and some generalization. This book deals with such materials that are commonly used in electrical engineering field. The decision upon the broad classification of materials in this book is done by first listing the functions of electrical engineering materials.

TYPE

PROPERTIES

TYPICAL EXAMPLES

METALS

Typical metallic cluster ,high thermal and electrical conductivity ductile, high strength corrosion, resistance is poor , positive temperature coefficient 

Steel copper aluminium iron etc.

 

Non metallic inorganic materials (also referred as ceramics)

No cluster high strength even at high temperature excellent resistance to oxidation and corrosion good thermal and electrical insulator brittle.  

Oxide (Sio2, MgO, Al2O3, BaTiO3 ) silicate borides, nitrides, carbides.

Organic polymers

Easy to fabricated, good insulators, light in weight, good corrosion resistance, low strength, negative temperature resistance

Generally synthetic organic compounds rubber (natural polymer).

 

Composite (combination of above various verities of materials

Many unusual combinations of properties can be accomplished by the suitable design of a composite.

Strong carbon fifers embedded in plastics, concrete, wood (naturally occurring composite.)

 

(1) To transmit electricity.

(2) To resist the flow of electricity except in a particular direction

(3) To store electrical energy.

(4) (A) to transfer electrical energy from one circuit to another,

     (B) To change the form of energy,

(5) To change nature and level of electrical signals.

Analyzing the above, a function classification of electrical engineering materials can be made as follows:

(1)         The materials which, allow the CURRENT to pass through them, are called conducting materials. These have very low electrical resistance and available in large variety having diverse properties. The conducting materials should be able to withstand high temperatures and on the other hand should have minimum power loss even when carrying large Nichrome currents. Examples: copper, aluminium, silver, gold, tungsten, platinum, tantalum, bronze, brass, steel, lead, mercury etc.   

(2)         The materials which obstruct the flow of current without any appreciable power loss are classified as insulating materials. These have very high electrical resistance and are available in large variety. Examples: rubber, Glass, Asbestos, Bitumen, Wood, etc.

(3)         The materials, which store electrical energy, are classified as dielectric materials. They increase the capacitance or charge storage ability of a capacitor. Examples: air, mica, ceramic, plastic etc.

(4)         The materials which provide a path to the magnetic flux are classified magnetic materials. Many electrical engineering devices such as inductors, transformers, rotating machines and ferrite antennas are based on utilizing the magnetic properties of materials. Examples: iron, high carbon steel, tungsten steel, cobalt steel, barium ferrite, chromium steel etc.

(5)         The material which possess electrical resistivity in between the conducting and insulating materials are classified as semiconductor materials. They are used for the manufacturing of devices like diode, transistors, rectifier etc. Examples: silicon, germanium, graphite, diamond, selenium, silicon, carbide, gallium phosphate, gallium arsenide, cadmium sulphide, etc.

Posted Date: 7/9/2012 7:10:56 AM | Location : United States







Related Discussions:- Engineering materials and engineering materials properties, Assignment Help, Ask Question on Engineering materials and engineering materials properties, Get Answer, Expert's Help, Engineering materials and engineering materials properties Discussions

Write discussion on Engineering materials and engineering materials properties
Your posts are moderated
Related Questions
In a young's double slit interference pattern, the fringe width is 0.1 mm. Determine the fringe width if the wave length of light is increased by 10% and the distance between the s

Energy Conservation on an Incline In the given case of the cart rolling down predispose and there are three external forces (the general force, the force of friction and air re

B-Infrared (IR)  Radiant Heat Heat radiation can be achieved by using infrared (IR) radiation it penetrates about 3mm in the skin. excessive exposure can cause erythema(redden

Is there any experiment to tell that water can move from lower concentration to higher Which means flows back to mountain without reversing time Could water flow upward by itself w

An ice-skater with a moment of inertia of 1.1 kg/m2 starts to spin with her arms extended. After 25 s, she has an angular velocity of 15 rev/s. What is the net torque acting on

Specified a set of equipotential surfaces how does one determine the corresponding set of electric field lines? Feedback: An equipotential surface signifies a set of poin

i want to do experiment online

how are digital signal are periodic and non periodic signal

The Diamond Structure The diamond cubic structure is a distinctive of materials that have its constituent materials  bound in tetrahedral bonds. Insulators like carbon, semicon

An alternating voltage is triangular in shape, rising at a constant rate to a maximumof 300V in 8ms and then falling to zero at a constant rate in 4ms. The negative half cycle