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really, I agree with Dillip.. before giving further answers, newcomers are invited to read the whole discussion and not the last 3 comments.. this would save lot of time and would definitely contribute to make ResearchGate a useful tool....
You are not forced to answer a question you see because "you know an answer". On the other hand you are invited to do it when you can contribute with something original (or overlooked) to the discussion. This usually imply you are an expert in that field or you have sufficient expertise to provide some accurate point of view or to properly correct/integrate what other have said.... -
It is for every scientist,nothing new. -
Here is another reference for arc producing Cu nanoparticles. Electric arc is probably the simplest way for producing nanoparticules.
Journal of Nanomaterials
Volume 2010 (2010), Article ID 403197, 5 pages
doi:10.1155/2010/403197
Research ArticleEffects of Current on Arc Fabrication of Cu Nanoparticles
Exploding a metal wire in a gaz or liquid with a current pulse is also a very simple way to get nanoparticles.
Carbon black contains large amount of nanoparticles. -
Simple addtion of metal transition atoms in diamagnetic matrix gives place to magnetic nanoparticles. -
dear Charles
I already mentioned the exploding wire methos that we used at end of the seventies -
The mechanical method is a cheap method and it gives very good results -
High energy mechanical alloying/milling -
Laser ablation is great - but what if you do not want them (NPs) on substrates/in a matrix...
Anyway - consider also detonation synthesis (v. expensive & you get very little sample afterwards)... Ion implantation (NPs on substrate/surface - see sor example https://www.researchgate.net/publication/232403726_Formation_of_cBN_nanocrystals_by_He_implantation_into_hBN?fulltextDialog=true&ev=prf_pub_xaddfulltext and https://www.researchgate.net/publication/230580008_Mechanical_and_Structural_Properties_of_Fluorine-Ion-Implanted_Boron_Suboxide/file/9fcfd5019561b972bf.pdf?ev=pub_int_doc_dl&docViewer=true) -
I hope this reply is helpful to your research. -
The use of an ultrasound instrument may also assist with the physical bombardment of larger particles into nanoparticles. This is a frequency-dependant process in order to achieve the desirable particle size distribution. Depending on the material properties you would need to select either impact force methods or compression force methods.
Popular Answers
The 'bottom-up' variety of physical techniques can be classsified into the following two categories:
(1) Spray techniques such as spray dry, freeze dry, plasma spray and hot spray.
(2) PVD-based techniques are particularly suitable for obtaining nanocrystalline thin films. They include Evaporation-Condensation, CVD and PE-CVD, Laser Ablation and Magnetron Sputtering. Of these, the last is by far the most versatile. One can obtain nanocrystalline films of most metals (dc sputter), oxides, nitrides, sulphides etc. (rf sputter) either using reactive sputtering or from targets having the same composition. Low substrate temperatures, high sputter-gas pressure and low energy conditions generally favour smaller particles. But if you are looking for a cheaper technique without sophisticated instruments, chemical techniques are better and provide larger yield.
Several reviews are available on this topic. Some representative references are added below (I have chosen older references that give more details).
1. SPUTTERING: (i) Hahn & Averback, JAP 67 (1990) 1113, (ii) Ayyub et al., Appl Phys A 73 (2001) 67; Scr. Mat, 44 (2001) 1915
2. LASER ABLATION: (i) Koshizaki et al. J Phys Chem B 107 (2003) 9220; Appl Phys A 76 (2003) 641
3.SPRAY DRYING: Okuyama et al. Chem Engg Sci. 58 (2003) 537.
4. INERT GAS CONDENSATION: Siegel et al. J. Mat. Res. 6 (1991) 1012.
J. Appl. Phys. 109, 094302 (2011)
Phys. Rev. B 79, 235409 (2009)
J. Appl. Phys. 100, 084311 (2006)
Phys. Rev. B, 71, 125420 (2005)
and references therein.