Such as ZnS has melting point in bulk is it would change in nano.
It seems that the melting point of nanostructured materials should decrease in comparison to the same materials with larger grain sizes. Because, as the size of the crystallites (or grains) decreases, its surface area increases and it means that the grain boundaries which are not ordered places, will increase. Grain boundaries are places that composed of plenty of point defects and linear defects (dislocations). Chemical bonds among atoms and crystal structures are two factors that determine the melting point of material. Moreover, melting point is a point that material has not a long range order and crystal structures will diminish. When a sample has any kind of defect, it means that plenty of atomic bonds are broken. Therefore, defects can decrease the melting temperature.
According to this concept for a single material, the melting temperature of single crystal which is perfect should be higher than its polycrystalline condition; and the melting point of a polycrystalline structure should be higher than a nanostructured one.
Thanks but is it means that thermal properties of the material does not change
You may know some materials are restricted to be studied in thermal study because of their effect on sensors such as metal chalcgenide
Please go through the following link and also check the references therein:
http://www.dstuns.iitm.ac.in/teaching-and-presentations/teaching/undergraduate%20courses/vy305-molecular-architecture-and-evolution-of-functions/presentations/presentations-2007/seminar-2/P10.pdf
It seems that the melting point of nanostructured materials should decrease in comparison to the same materials with larger grain sizes. Because, as the size of the crystallites (or grains) decreases, its surface area increases and it means that the grain boundaries which are not ordered places, will increase. Grain boundaries are places that composed of plenty of point defects and linear defects (dislocations). Chemical bonds among atoms and crystal structures are two factors that determine the melting point of material. Moreover, melting point is a point that material has not a long range order and crystal structures will diminish. When a sample has any kind of defect, it means that plenty of atomic bonds are broken. Therefore, defects can decrease the melting temperature.
According to this concept for a single material, the melting temperature of single crystal which is perfect should be higher than its polycrystalline condition; and the melting point of a polycrystalline structure should be higher than a nanostructured one.
Melting point decreases with the reduction of particle size. For details please check the following review paper last chapter (chapter 7)
http://www.sciencedirect.com/science/article/pii/S037015731100010X
Not much effect will be there on the melting point. It is a structure insensitive property.
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