Wet comminution in a colloid mill.

For industrial-scale reduction of Si₃N₄ powder from 3 µm to finer sizes suitable for tape casting, wet ball milling is typically one of the most effective methods, as it is scalable, relatively cost-effective, and allows for good control over particle size distribution. You can use a dispersant in the milling medium to prevent agglomeration and achieve a uniform dispersion of the fine powder.

Alternatively, if finer particle sizes (in the sub-micron or nano range) are required, jet milling or high-energy ball milling could be considered, though these methods may involve higher operational costs and more complex equipment.

Finally, ensure that the powder is well-dispersed in the slurry for tape casting to prevent defects in the final silicon nitride substrate.

Thank you for suggestions

Best Choice: Wet Ball Milling or Attrition Milling for industrial scale due to cost-effectiveness and ability to control particle size.

Tips: Use dispersants (e.g., PVA, PAA) to prevent agglomeration and ensure slurry stability for tape casting. Optimize milling parameters to avoid contamination.

Mechanical milling and laser Ablation depends upon size of power particles first one is economical

Try using a suspension of the resulting powder in water (or alcohol, or acetone).

After an hour, the large particles will settle, and the small ones will remain in suspension. Dry it. These will be small particles...

After 2 hours, very small particles will remain in suspension.

You can use ball milling if the material is in powder form.

Mohammed Abd You cannot dry mill below the so-called ‘comminution limit’. Google this term...

Thank you all for your suggestions.

My suggestion is that one can try the Application High Intensity Ultrasound for this purpose of particle size reduction.

You can use ultrasonic irradiation (sonochemistry), sonofragmentation to nanoparticles.

Exactly!.... I really appreciate your recommendation.... I worked with high frequency and intensity ultrasonic testing and characterisation. But definitely I know that this low frequency and high intensity app. 1000 Watts would be useful for this particle size reduction.

Sajid

Arun's answer is pretty good. Do some library and patent rearch. you will find lots of patents on ball-miliing of carbides and nitrides including silicon nitride.

Prof Dr K