Diamond micron powder is synthetic diamond graded in micrometre ranges, normally from W50 down to W0.1, and sold by measured particle-size distribution rather than by mesh count. The grade name only gives you a nominal size window. The certificate and a controlled sample tell you whether the powder will behave in your process.
Where Micron Powder Starts
Diamond abrasive is split into two commercial worlds. Coarse material is sold by mesh count and goes into bonded tools where each particle has to carry a mechanical load. Fine material is sold by micrometre range and goes into lapping, polishing and slurry work where surface finish and scratch control matter more than single-particle strength.
In the DiamondHX product table the micron range starts at W50, which is nominally 50 micrometres, and runs down to W1 at one micrometre. Below that, nano grades take over: HDYM and HDYMC cover W0.5 to W0.1, and HDPN covers 5 nm to 500 nm. The overlap around 40 to 50 micrometres is the practical border, because 325/400 mesh grit and W50 powder describe roughly the same particle size from two different directions.
The Four Product Families
Almost every micron powder inquiry lands in one of four families. They are not marketing tiers. They behave differently in the same machine.
| Family | Codes | Size range | Crystal | Typical route |
|---|---|---|---|---|
| Yellow monocrystalline | HDY, HDYR | W50 – W1 / 80/100 – 325/400 mesh | Mono | General lapping and polishing |
| Type II yellow monocrystalline | HDH, HDHR | W50 – W1 / 80/100 – 325/400 mesh | Mono | Same route, different raw material batch |
| Black monocrystalline | HDG, HDGN, HDGR, HDGNR, HDGD | W50 – W1 / 50/60 – 400/500 mesh | Mono | Cost-driven polishing, black appearance |
| Polycrystalline and nano | HDYP, HDP, HDPN, HDYS, HDRP | 0.7 – 40 um / 0 – 1 to 1/8 um / 5 – 500 nm / 20 – 50 um / 0 – 2 to 40 um | Poly | Mirror finish, low scratch depth |
Monocrystalline powder is milled from a single crystal, so each particle keeps sharp, well-defined cutting edges. Polycrystalline powder is built from many smaller crystallites; as the outer edges dull, the particle fractures and exposes fresh cutting points. That is why poly grades are usually tested when the surface requirement is a mirror rather than a removal rate.
Typical Sizes By Process
Buyers often ask for a size before they describe the process. The process is the better starting point, because two factories running the same nominal grade at different pressures and pad conditions get different results.
| Process step | Typical size | Grade direction |
|---|---|---|
| Coarse lapping, stock removal | W28 – W50 | HDY, HDG |
| Precision lapping | W7 – W20 | HDY, HDG, HDYP |
| General polishing | W1 – W5 | HDY, HDYP |
| Mirror and final finish | W0.5 – W1 | HDYM, HDYP, HDP |
| Wafer and CMP slurry | 0.5 – 3 um and finer | HDYP, HDP, HDPN |
These are starting points, not specifications. Wire sawing is a good example of how specific the real answer gets: silicon and sapphire wire slurries commonly run 6 to 12 or 8 to 16 micrometres, and the powder usually carries a nickel coating so the grit stays attached to the wire.
What The Grade Name Does Not Tell You
Two suppliers can both ship a bag labelled W10 and hand you powders that behave differently. The grade name describes a nominal window, not a distribution. What actually changes the result is the shape of the curve behind that label:
- D50 sets the removal rate you will feel first.
- D90 and D97 set how many oversized particles are in the bag, and therefore how many deep scratches you will have to polish out.
- D10 sets how much fine material is present, which affects slurry stability and how quickly the cut slows down.
- Morphology decides whether the particle cuts, ploughs or fractures.
Common Mistakes
- Ordering by grade name only. “W10” is not a specification. Without D50 and D97 you are not comparing two products, you are comparing two labels.
- Assuming finer is always better. If the powder agglomerates or carries oversized particles, a finer grade can produce more scratches than a coarser clean one.
- Changing size and carrier at the same time. Moving from W14 dry powder to W7 slurry changes two variables at once, so the trial tells you nothing about which one fixed the surface.
How To Verify Before You Order
- Ask for a laser-diffraction PSD report for the exact lot, not a catalogue page. D10, D50, D90 and D97 are enough to compare.
- Ask for a morphology image at the size you are buying. Shape at W1 is not the same as shape at W40.
- Ask how ash content is controlled. Measured ash on high-strength grit typically sits between 0.0002% and 0.0093%, and it matters more in slurry and coating work than in bonded tools.
- Run a sample on your own machine with your own pad, pressure and slurry chemistry. Polishing results do not transfer between machines.
Next Step
If you already know the process, go straight to the grade family: HDY monocrystalline micron powder for general lapping and polishing, HDYP polycrystalline powder for mirror finishing, or HDYM nano powder for the final sub-micron step.
If you are still matching the process to a product, start from resin and vitrified bond wheels or carbide and ceramic polishing, and read how mesh and micron sizes relate before you write the inquiry.