Properties of Nano Materials.pptx

Properties of Nano Materials,super plasticity etc

1. Properties of nanomaterials  GERUGANTI NIKSHITHA B.TECH(ELECTRICAL ENGINEERING),GNITS,HYD.

2. The properties of nanomaterials depend upon : Size  For example: copper nanoparticles smaller than 50nm are super hard  Materials and do not exhibit the properties of mallaebility or ductility of bulk copper

3. The different types of properties shown by nanomaterials are:

4. Physical properties of nanomaterials  By  reducing the size of the particle the surface to volume ratio increases. This changes the surface pressure ,resulting in decrease in the interatomic spacing . The change in inter atomic spacing and large surface to volume ratio have a combined effect on material properties such as,

5. Melting point: The melting point decreases with size and at very small sizes the decrease is faster

6. Chemical properties

7. Chemical properties In small positively charged clusters of Ni, Pd and Pt can absorb up to eight hydrogen atoms per metal atom The number of absorbed atoms increases with decrease in cluster size This shows that small particles are very useful in hydrogen storage devices in metals 

8. Quantum well, wire,dot

9. Electrical properties

10. Electrical properties In the figure we see that due quantum confinement the energy levels narrow down and become discrete when we move from bulk to dot Tn nanomaterials the electrical conductivity increases with reduction in particle size 

11. Optical properties Depending on the particle size ,different colors are seen for example gold nano spheres of 100nm appear orange in colour while 50 nm nanospheres appear green in colour Particles can be made to emit or absorb a specific wavelength by controlling their size  This Photo by Unknown author is licensed under CC BY-SA .

12. Magnetic properties Nano materials show high coercivity and magnetization values These values  increase with decrease in the grain size and an increase in the specific surface area of the grains  The magnetic moment of Co particles of approx 2nm exhibited 20% higher value than that of bulk  Nano particles of even non- magnetic solids are found to be magnetic 

13. Mechanical properties If the grains are nanoscale in size ,the interface within the material greatly increases, which enhances the strength For example: nanocrystalline nickel is as strong hardened steel Decreasing hardness with decreasing grain size in the nanoscale grain regime Superplastic behaviour of ceramic

14. Superplasticity