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submicron alumina particle size

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klmchem

Materials
Mar 8, 2004
6
US
I am trying to obtain a submicron particle size for alumina. I am using a mixture of about 60% water, 30% alumina, 5% Petro D-425 and 5% Witconol 14(from Akzo Nobel). I am not fixed on 30% alumina, but I would not want to go below 15%. I have milled my mixture twice and have obtained a mean particle size of 3.3 microns. I would like to see results of around 100-200nm, without having to mill more than two times. I am shooting for a white pourable dispersion for the end result. Any suggestions on this matter would be greatly appreciated. Thanks in advance.
 
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You can purchase .05um Al2O3 from all metallography consumables suppliers, they also make other sizes i believe.

nick

Go here:

or just google metallography supplies
 
NickE,
I already have alumina in a pretty fine powder, and I don't think I have too much flexibility in changing it. Any suggestions on just working with what I have? Thanks.
 
As far as I know to get down to sub-micron sizes you will need to use a sol-gel process to produce the powder. This is because the energy needed to increase the surface area at each grinding (milling) step goes up exponentially.

I wouldn't really consider your current 3.3um powder pretty fine at all. It's 22x bigger than what you want. you might try a SPEC mill, using Al2O3 balls in a Al2O3 lined container with enough energy "might" get the size distribution you want.



nick
 
NickE,
The alumina that I am using is about 8um in the powder form. We are using this form (pseudo baumite) for its properties, and from our standpoint it is the best chose for our end use. We do not have a lined mill, we have a horizontal and Netzsch mill, I have been using the Netzsch mill. Would you suggest using the Al2O3 balls in that mill? Thanks.
 
I'm not aware of what a Netzsch mill is. My guess as to what a horizontal mill is that its a horizontla ball mill.

The problem with the standard ball mill in producing fine ceramic particles is that you cant deliver enough energy to the particle w/o destroying the ball and with metal balls this causes contamination. You might get a ball mill to produce a fine enough powder size.

When I had Communution & Separation in university the standard rule of different communution machines was:

Jaw Crushers
Gryratory
Cone Mill
Rod Mill
Ball Mill
Autogeneous Mill
Pebble Mill
High Pressure Roll Mill
Attritor
Vibratory Mill
SPEC Mill (Sample Preparation Extraction & Communution)
Sol Gel
Vapor Deposition


with jaw crushers producing the largest particle size and Vapor Deposition producing the smallest. The Attritor is able to achieve <um sizes. (or at least thats what I wrote in these notes from class 10years ago)

Thats the limit of my knowlege. I have done some sampling since school but not size reduction.

nick
 
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