Nitika . NdFeB is highly magnetic, so dry measurement is the preferred route. Method development does not use an SOP; instead you develop the method using a pressure-size titration (PST). For further information, view this webinar (free registration required):

PST & BDAS - An acronym approach to laser diffraction method development

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190815PST

https://tinyurl.com/y67v3324

Hi !

To measure NdFeB powder particle size using the Microtrac Sync analyzer, you have to disperse the powder uniformly in a suitable non-reactive dispersant (e.g., isopropanol or ethanol) under ultrasonication to prevent agglomeration. Then, load the suspension into the analyzer, select laser diffraction mode, and run the measurement under optimized obscuration and scattering settings for accurate size distribution.

Mani Sharma Wet method will not work for NdFeB as it is highly magnetic and this will overcome any dispersion attempts in the wet. As soon as you relax the sonication the particles will be attracted to each other. Try it and see - if the wet and dry results agree then the material is in the same state of dispersion in both cases.

What about using scanning electron microscopy on the material. Yes, the material will probably be agglomerated, but SEM should show you the size nature of the constituent particles.

You may need to use a small amount of material, if it is magnetic. Large amounts could alter the fields inside the SEM and make imaging difficult.

You should also make certain the particles are firmly attached and use a longer working distance. You don't want to suck particles up into the column.

Warren Straszheim Nitika . Some form of imaging is always essential in order to get a handle on the form/shape of the constituent particles. One needs to remember that a number-distribution is obtained and that isn't the same as a volume distribution provided by laser diffraction. See attached.

Thank you all for your helpful responses and suggestions Alan F Rawle Warren Straszheim Mani Sharma . I have already performed SEM imaging on the NdFeB powder, which confirmed that the particles appear agglomerated. The material has been demagnetized prior to analysis. My aim is to obtain the particle size distribution, and I am currently leaning toward dry measurements rather than wet dispersion.

I will go through the files you have shared and also look into PST. However, if anyone has a simpler, straightforward technique for just running the Microtrac Sync with NdFeB powder, I would be very interested to hear about it.

Nitika . Rather than all this discussion, gather some experimental data, then report back. “In theory, theory and practice agree. In practice, they do not...”