We have synthesized alumina and NiO nanoparticles by solution combustion method using two different fuel i.e, urea and glycine. We observed different kind of morphology for alumina and NiO with different fuel. Can any one help me to get answer?
Dear Dr. Raveendra:
After ignition it is possible gives a general picture: the final temperature and the time of operation of combustion are determining in the powder morphology.
i) if the temperature increases, small particle tend to develop some kind of coalescence, it is interesting since is a conventional manner of particle (nanoparticle) to growth. However, concurrent and/or parallel take place, that leads to start aggregate and at sufficient temperature, agglomerate. Then, the powder might exhibits "original" nanoparticles, coalescencent particles and secondary ones, agglomerates and secondary ones, aggregates and if temperature is very high sintered agglomerates.
ii) as a function of type fuel distinct final temperature can be drive the particle (nanoparticle) formation and its growthing. Different fuels can be used but the ones highly oxygenate or complex that very, very exothermic characteristic "should" be avoided.
iii) as a function of amount of fuel, the high temperature of combustion can be sustained during long time, or by time beyond of necessary, that allow the actuation of mechanisms above commented agglomerate formation, aggregate formation and agglomerate sintering
iv) sometimes balance between amount of oxide particles to be synthesized and fuel amount is not optimized, this condition is fundamental. Some interfering can be actuate when precursor are changed from original raw material.
v) sometimes particles of typical refractory materials as actuate as a damper of reaction since free thermal flux blocked.
Kind regards
Marcos Nobre
Dear Dr. Raveendra:
After ignition it is possible gives a general picture: the final temperature and the time of operation of combustion are determining in the powder morphology.
i) if the temperature increases, small particle tend to develop some kind of coalescence, it is interesting since is a conventional manner of particle (nanoparticle) to growth. However, concurrent and/or parallel take place, that leads to start aggregate and at sufficient temperature, agglomerate. Then, the powder might exhibits "original" nanoparticles, coalescencent particles and secondary ones, agglomerates and secondary ones, aggregates and if temperature is very high sintered agglomerates.
ii) as a function of type fuel distinct final temperature can be drive the particle (nanoparticle) formation and its growthing. Different fuels can be used but the ones highly oxygenate or complex that very, very exothermic characteristic "should" be avoided.
iii) as a function of amount of fuel, the high temperature of combustion can be sustained during long time, or by time beyond of necessary, that allow the actuation of mechanisms above commented agglomerate formation, aggregate formation and agglomerate sintering
iv) sometimes balance between amount of oxide particles to be synthesized and fuel amount is not optimized, this condition is fundamental. Some interfering can be actuate when precursor are changed from original raw material.
v) sometimes particles of typical refractory materials as actuate as a damper of reaction since free thermal flux blocked.
Kind regards
Marcos Nobre
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