Diamond Powder
Loose diamond powder for metallographic polishing and lapping, in synthetic (monocrystalline), polycrystalline, and natural grades. Supplied dry, graded by micron size, and sold by the carat (25 to 100 carats per bottle), our diamond powder lets a lab charge cloths and laps, mix custom suspensions and pastes to a chosen concentration, and buy in bulk for a lower cost per use. Comparable to the diamond powders from Buehler, Struers, and Allied High Tech, typically 20 to 40 percent lower in price. Used across metallography, ceramics, optics, and tool-and-die lapping.
Diamond Type Selection
Diamond type controls cutting action and the amount of subsurface deformation left behind. Match it to the material and how critical the finish is.
| Type | Crystal Structure & Cutting Action | Best For | Micron Range |
|---|---|---|---|
| Synthetic (monocrystalline) | Single-crystal particles with defined facets; sharp, aggressive, predictable cutting at a high removal rate. | General-purpose polishing of hard and brittle materials — carbides, ceramics, hardened steels. | 1/10 to 70 micron |
| Polycrystalline | Many micro-crystals per particle that fracture to expose fresh edges (self-sharpening); high removal with a finer scratch pattern and less subsurface deformation. | Hard, mixed-phase materials and deformation-sensitive work (EBSD, TEM prep). | 1/10 to 45 micron |
| Natural | Tough, blocky natural crystal; the traditional, durable option where a procedure specifies natural diamond. | Established procedures and general lapping. | 1/10 to 70 micron |
Micron Size and Polishing Step
Diamond polishing runs coarse to fine, each step removing the scratch pattern from the one before it. A typical sequence uses 30 or 9 micron for the first diamond step after grinding, 6 or 3 micron for the intermediate step, and 1 micron (down to 1/10 micron) for the final diamond polish before any oxide step. Verify each step is clean at 50–100× reflected light before advancing.
How Diamond Powder Is Used
Powder is sold by the carat in bottles of 25, 50, 75, or 100 carats. Charge it directly onto a polishing cloth or lap, or mix it into an oil-, water-, or alcohol-based carrier to make a suspension or paste at your chosen concentration (carats per unit volume). Buying powder is the most economical route for high-volume steps and for building custom concentrations that pre-mixed suspensions do not offer. Beyond metallography, graded diamond powder is used in ceramics, optics, and tool-and-die lapping.
Frequently Asked Questions
Which diamond type should I use?
Use synthetic monocrystalline for general-purpose sharp cutting on hard, brittle materials; polycrystalline for high removal, a finer finish, and lower subsurface deformation on hard, mixed-phase materials and EBSD/TEM work; and natural where a procedure specifies it. All three are graded to the same micron sizes, so you can substitute type without changing your step sequence.
How do I charge a cloth or mix a suspension from powder?
Charge the cloth by applying a small amount of powder with a compatible lubricant and letting the cloth distribute it before polishing. To make a suspension or paste, disperse the powder into an oil-, water-, or alcohol-based carrier at your target concentration in carats per volume. Selling by the carat lets you set concentration exactly and buy in bulk for a lower cost per sample.
What micron size goes with which step?
Use 30 or 9 micron for the first diamond step after final grinding, 6 or 3 micron for the intermediate step, and 1 micron down to 1/10 micron for the final diamond polish. Follow with a 0.05 micron alumina or 0.06 micron colloidal silica oxide step only when a deformation-free surface is required.
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