Phosphor materials exposed to high temperature for few hours and suddenly brought to room temperature. I want know the effect of it on luminescence properties of phosphor .
Hi,
In in rapid quenching you can have fine grains size, which is relatively stronger than coarse structure.
best
V R Arun Prakash Thanks for your answer...My question is related to phosphor material obtained by doping of a rare earth material... What I think that grain size of phosphor material is decided by the temperature and reaction time ( Co precipitation method) ...once we get some powder then it is subjected to high temperature and then rapid quenching ..I want to know is there any effect on doped impurity rare earth ion distribution in phosphor matrix? kindly send references if available.
Solid solubility of a alloying element changes with temperature,
On annealing temperature (Above recrystallization temperature - very close to melting point), Alloying element will have more solubility limit. That is a liquid with a high percentage of solute in the solvent.
Holding at this temperature, make diffusion of atoms (Movement of atoms from high concentration to lower concentration), This makes the uniform distribution of alloying elements in the alloy. and also remove micro voids. this process also called Solutionizing .
Now come to quenching process: quenching, is a rapid cooling process, this is to form a Super saturated solid solution - the whole objective of the rapid cooling is this - this is the answer to your question
Now the questions are
1. what is solid solution and
2. what is Super saturated solid solution
Solid solution: two elements (example Mg and Al), where Mg is solute, Al is a solvent, they co-exist together as a single phase, here in this example case is a substitutional solid solution.
Super saturated solid solution (SSSS): is the excess amount of Mg present in the Al matrix is called SSSS.
(Supersaturation is a solution that contains more of the dissolved material than could be dissolved by the solvent under a specific temperature)
Now again coming back to rapid cooling (Quenching), dont allow or do not have time to the dissolved solute atoms to move back from the solvent at lower temperature and thus forming a ssss rather than the precipitates of solute atoms
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