Zirconium silicate or Zircon is a not-so-commonly used coarse grinding abrasive. Because of its extreme toughness, it lasts longer. But, it isn’t, in general, as hard or sharp as the more popular abrasives. It thus needs a higher pressure to be effective. Usually, the 120 or 60 grit sizes are considered the most useful for metallographic grinding applications with Zircon.

The particle size for metallographic abrasives is classified typically by their grit size or the average particle size measured in microns. Grit size refers to the particle size if sized or classified with mesh screens. Grit size, in general, represents the number of wire mesh or wires per given area. Larger grit numbers thus represent more or smaller mesh screen openings, and mean smaller particle sizes.

For instance, a 120 grit particle is around 105 microns in size, while a 1200 grit particle is 2.5 microns in size. The variance between the P-grading system used in Europe and the more prevalent CAMI or ANSI standard is mainly due to the European number being based on how many openings there are if the wire mesh width is not considered in the calculation.

For larger particles, therefore, Europe’s P-grading is about the same as the CAMI or ANSI number. For example, 120 grit is equivalent to P120 grit. For finer particles, on the other hand, you will see a much bigger value such as P4000 grit compared to 12000 grit.