Materials Science – Role & Its Importance Dr. A. R. Koppalkar, Associate Professor, Department of Physics, S. S. Margol College, Shahabad International Year of Chemistry – V. G. Womens College Gulbarga –

What are Materials? That’s easy! Look around. Our clothes are made of materials, our homes are made of materials - mostly manufactured. Glass windows, vinyl siding, metal silverware, ceramic dishes… Most things are made from many different kinds of materials.

Materials Science Defined as the study of the properties of materials and to have a proper application of the same materials. These properties are determined by a material’s composition and structure.

Materials Science Example - the dramatic role of iron throughout the ages is not really the result of it being "strong". In reality, iron has been important because we can change its properties by heating and cooling it. The ability to change the properties and/or behavior of a material is what makes most materials useful and this is at the heart of materials science!

Materials Science An interdisciplinary study that combines metallurgy, physics, chemistry, and engineering to solve real-world problems with real-world materials in an acceptable societal and economical manner.

Kinds of Materials Metals: are materials that are normally combinations of "metallic elements". Metals usually are good conductors of heat and electricity. Also, they are quite strong but malleable and tend to have a lustrous look when polished. Ceramics: are generally compounds between metallic and nonmetallic elements. Typically they are insulating and resistant to high temperatures and harsh environments.

Kinds of Materials Plastics: (or polymers) are generally organic compounds based upon carbon and hydrogen. They are very large molecular structures. Usually they are low density and are not stable at high temperatures. Semiconductors: have electrical properties intermediate between metallic conductors and ceramic insulators. Also, the electrical properties are strongly dependent upon small amounts of impurities.

Kinds of Materials Composites: consist of more than one material type. Fiberglass, a combination of glass and a polymer, is an example. Concrete and plywood are other familiar composites. Many new combinations include ceramic fibers in metal or polymer matrix.

Newer Branches of Materials Science Nanotechnology: a relatively new area grown out of techniques used to manufacture semiconductor circuits. Machines can be produced on a microscopic level. Example - miniature robots to do surgery inside the body or miniature chemical laboratories and instruments that will continuously analyze blood and dispense medications inside the body.

Materials Science The following elements and their interaction define Materials Science –Performance –Properties –Structure and composition –Synthesis and processing

History of Materials Even our history has been defined by the materials we use… The stone age The copper age The bronze age The iron age What would be a good material name for today?

History of Materials Man has been studying materials since before leaving the cave. Due to lack of communication, early man spent hundreds of millennia experimenting with stone tools. The first metal tools appeared perhaps only six thousand years ago.

Engineering Materials Ferro Electric Ceramics Polymer Composites Ferro Magnetic Materials Nuclear Materials Super Conducting Materials

Ferroelectric Ceramics Materials  In these materials the crystal structure is such that the centers of positive and negative charges do not coincide even in the absence of external electric field.  They have considerably high values of dielectric constant and exhibit hysteresis behaviour with the application of electric field.

Properties used in applications Dielectric, Piezoelectric, Pyroelectric, Electro-optic Applications Capacitors, Cigratte and Gas lighters Non volatile memories, Micropositioners Transducers, Piezoelectric Transformers Impact Printer Head, etc.,

Polymer Composites  Conductive polymers are organic polymers that conduct electricity.  The biggest advantage of conductive polymers is their processability.  Conductive polymers are also plastics and therefore can combine the mechanical properties of plastics with high electrical conductivities

The advanced Polymer composites are Polyethylene composites (PEO) Polyaniline composites (PANI) Polypyrrole composites(PPY) Polyvinyl acetate composites(PVA)

PEO based composites PEO based batteries PEO+LiAsf6 Chemical structure of PEO

Polyaniline composites (PANI) Structure of polyaniline PANI-LED

Different preparation techniques leads to different surface area Bulk -HCl Nano fiber -SDBSAH 3 PO 4 HNO 3 Succanic acid H 2 SO 4 Prepared in our lab

PANI / CdO; PANI/n-TiO 2 & PANI / n-ZnO Composites Prepared in our lab

Application

GAS SENSOR

A gas sensor is a chemical sensor that is operated in the gas phase. It converts chemical information, which is determined by different concentrations of gaseous chemical species, into an electrical signal [6]. Thus, a chemical sensor gives a signal that in some way is related to the chemical environment it is exposed to.

GAS SENSOR

Polypyrrole composites(PPY) Structure of polypyrrole

PPY-Display

Polyvinyl acetate composites(PVA) Structure of polyvinyl acetate PVA Display

PVA Screen

Ferro Magnetic Materials Iron, nickel, cobalt and some of the rare earths (gadolinium, dysprosium) exhibit a unique magnetic behavior which is called ferromagnetism In ferromagnetic material, all the magnetic moments of the individual atoms or ions are aligned parallel to some particular direction Ferromagnetic materials exhibit a long-range ordering phenomenon at the atomic level which causes the unpaired electron spins to line up parallel with each other in a region called a domain

Ferro Magnetic Hysteresis Ferromagnets will tend to stay magnetized to some extent after being subjected to an external magnetic field. This tendency to "remember their magnetic history" is called hysteresis

APPLICATIONMS OF FERROMAGNETIC MATERIALS  Iron Core Solenoid  An iron core has the effect of multiplying greatly the magnetic field of a solenoid compared to the air core solenoid on the left.

Shape Memory Alloy A shape memory alloy (SMA)is an alloy that "remembers" its shape, and can be returned to that shape after being deformed, by applying heat to the alloy. When the shape memory effect is correctly harnessed, this material becomes a lightweight, solid-state alternative to conventional actuators such as hydraulic, pneumatic, and motor-based systems. Shape memory alloys have numerous applications in the medical and aerospace industries.

Super Conducting Materials DISCOVERY –KAMERLINGH ONNES DISCOVERED SUPER CONDUCTIVITY IN 1911 WHILE STUDYING THE RESISTIVITY OF MERCURY CLASSIFICATION –TYPE-I AND TYPE-I superconductors –LOW Tc & HIGH Tc superconductors

COOPER PAIRS A model of Cooper pair attraction A passing electron attracts the lattice, causing a slight ripple toward its path. Another electron passing in the opposite direction is attracted to that displacement.

APPLICATIONS STORAGE OF ENERGY

TRANSMISSION OF ENERGY Super Conducting Cables

MAGNETIC LEVITATION Magnetic levitation Maglev Train