firstly, i want to know that what particle size of Al2O3 initially i should take for ball milling.
Secondly, i want to know that is that there is possibility of contamination if i make 70-80 nm Al2o3?
Thridly, is there any chances of agglomeration during milling of such powder and how i can deal with it?
fourth, how can i make separation of micro and nano particles?
1. Initially the powder size need to be in micron and again this depends on the size and the material you are using for milling
2. The contamination depends on the milling unit and the balls you take for milling . generally i would suggest you go for chemical route for better purity
3. Yes there will be agglomeration, you can avoid it by adding proper surfactant
4. you can separate the the different size powder by sieves or else you can go for ultrasonification
1- Ball milling is usually used to reduce the crystallite size from micro to nanometer scale. So, you can use micrometer powders.
2- The contamination of your powders depends on the ball milling tools (vials and balls) and/or atmosphere.
- You can avoid agglomeration by adding an agent to your powders during the ball milling such as methanol, etc.
- You can separate the particle size of the powders by using a particle size analyzer.
Dear all
1. i am using tungsten carbide balls for crushing 40 micron alumina
2. to prevent agglomeration i will use 3% wt acetone or methnol
3. i will run the process for 20 hr with 6 min run and 3 min stop to avoid temp generation.
is that okie i will get nano? can i go with it? i need spherical shape
Have you ever seen anything similar in literature? Standard wet milling techniques can probably reduce the particle size below 500 nm but you should not cherish the hope to go much further. You would have a good chance if you start not with coarse solid particles but with agglomerates of nanopraticles. For example, if you purchase something like TM-DAR grade alumina from Taimei Chemicals, you could indeed produce a dispersion of particles close to the primary size of about 100 nm specified by the manufacturer. Otherwise, if you are going start with strongly aggregated material in micrometer range, you can forget it.
Please consider also the reduction of the crystallinity of your particles for a longer milling time. Strain effect is also another issue. Some peoples are interested reasonable for surfactant assisted ball milling to avoid these issues.
most of the literature i studied they get flakes like nano particles. i think spherical shape is only possible with chemical routing only? i will try experiment with planetary ball milling but i am not sure will get spherical shape.
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