Larger and more resilient samples can be homogenized through the use of grinding balls. In contrast to grinding beads, which are a pool of beads within a given size range, grinding balls are spherical and precision ground to a specific diameter.
Grinding balls are made of stainless steel, tungsten carbide, or zirconium oxide, their larger size makes them more suitable for grinding, whereas beads have insufficient mass to accomplish this.
Prior to packaging, grinding balls are treated to remove residual oils and other contaminants.
|Characteristics||Stainless Steel||Zirconium oxide||Tungsten carbide|
|Size||2.8 mm (1/8") to 11.11 mm (7/16")||4 mm (5/32") and 6 mm (15/64")||
9.5 mm (3/8")
2.8 mm - 3 mm(1/8") - deep well plates and larger
4 mm (5/32") - 5 mm (13/64") - 2 ml tubes and larger
7.9 mm (5/16") - 9.5 (3/8") - 4 ml vials and larger
11.11 mm (7/16") - 15 and 50 ml vials
|2 ml Disruption tubes and larger||4 ml tubes and larger|
|Pros||Can be magnetic||Chemically stable, can be used with phenol and other acids||Most dense, ideal for extremely tough samples|
|Cons||Reacts with phenol and other acids||Lower density than metal balls||Reacts with phenol and other acids and expensive. Known to crack vials|