Because the nanoparticles of Mo fall in an agglomeration may this to hinder the sinters.
But, this particles are very small. So, what do you think about this?
If you are sintered pressed compacts of molybdenum, the compacts from nano-molybdenum will shrink more than that from the micro-molybdenum. This is because the pressed compact of nano-molybdenum has less dense than the micro-molybdenum. Most shrinkage is the only drawback of nano-molybdenum. In all other respects it is superior to a micro-molybdenum (preferably sintered and has a higher strength).
Hi Nicolas,
the smaller the particle size the lower the sintering temperature necessary for achieving a certain sinter density. But there are two disadvantages of a nano powder.
1) As Vadim mentioned the green density decreases with decreasing particle size and the shrinkage during sintering inreases.
2) For powders with a particle size smaller than FSSS 0.2 µm for larger green compacts coarsening of the grains occurs during the initial sintering phase, as on the one hand with decreasing particle size the gas permeability decreases (low transport rate of the oxygen from the center to the outside), and on the other hand the amount of oxygen adsorbed on the particle surface increases. This oxygen causes a gas transport process, whereby small particles decrease in size and larger particles increase in size. The sintering activity of such a coarsened structure is dramatically decreased, which results in a low sintered density.
Best regards
Gerhard
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanostructured Materials
- Nanoparticles