Осцилираща топкова мелница MM 500 nano

• Hardened steel (density 7.8 g/cm³; hardness ≤ 235 HB, medium abrasion resistance) 
  typically used for pulverizing medium-hard to hard and brittle samples. 
  
  
• Stainless steel (density 7.7 g/cm³; hardness ≤ 245 HB, medium abrasion resistance)
  typically used for pulverizing medium-hard to hard and brittle samples. 
  
  
• Tungsten carbide (density 14.8 g/cm³; hardness 93.6 HRA; high abrasion resistance) 
  used for grinding very hard, brittle sample materials. By using tungsten carbide, contamination of the sample with iron is prevented.
  
  
• Zirconium oxide (density 6.05 g/cm³; hardness 1250 HV, high abrasion resistance) ceramic material suitable for pulverizing medium-hard to hard and fibrous samples. It is typically used for heavy-metal-free grinding processes or applications which aim at ultrafine particle sizes. 

For cold grinding (cryogenic grinding) we recommend using the Cryo kit which consists of two transport aids, one insulated container (6 liters) as well as a pair of safety goggles.

Please only use grinding jars of hardened or stainless steel for cryogenic grinding. When using jars made of other materials, inner tension may build up and lead to damages of the jar under extreme temperature variations.

Attention:

First, the jar is filled with sample and ball(s), then the lid is screwed tightly, and the jar is immersed with the transport aid in the container filled with liquid nitrogen. After a few minutes (the liquid nitrogen should no longer boil) the sample has been indirectly embrittled inside the jar which can now be removed with the help of the transport aid and clamped into the mill (here, the transport aid is removed). Please never fill liquid nitrogen into the grinding jar because it evaporates and causes a considerable overpressure inside the jar.

Grinding balls and grinding jars should always be selected from the same material.

Grinding balls are available in different diameters. The rule of thumb is: for efficient milling the ball should be at least 3 times larger than the largest particle in the sample. To avoid abrasion and wear it is essential to only use balls with identical diameter.

The number of grinding balls depends on the jar volume used. The document “Grinding Jar Ball Charge” in the Downloads section provides details about usable volumes, maximum feed sizes and correct filling of the jars with grinding balls for dry and wet milling as well as cell disruption. For further information on materials please see the document “Material Analyses of Equipment & Accessories“ in the Downloads section.