Magnesium diboride

Because only 9 g of sample have been sent, we used the 80 ml bowl made of hardmetal tungsten carbide. For a grinding of higher amounts, up to 250ml grinding bowls can be used.

If abrasion of other grinding materials can be tolerated, up to 500 ml bowls use to be available in e.g. zirconium oxide or steel.

Only a grinding in suspension can be performed to achieve the desired fineness of d50 < 1 µm. For this, we added 10 ml of isopropyl alcohol to maintain a motor oil like slurry (for an optimum grinding result).

To avoid over pressure, we ground the sample in steps of 5 minutes, followed by a programmed pausing time of 10 minutes. After several cycles, the outside temperature of the bowl should be checked (remain below 70°C); grinding time or programmed pausing time might be readjusted afterwards.

After 30 minutes of grinding, we checked the present fineness with our Laser Particle Sizer ANALYSETTE 22. The target of d50 < 1 µm has been reached.