Polycrystalline diamond abrasive

Identity and material forms

Pureon’s detonation-synthesized Microdiamant DP 1.5–3 lists a particle D50 of 2.39 µm and D99 of 3.47 µm. The DP sheet describes primary crystals of approximately 20 nm within the particles. D99 describes a percentile, so the grade name and that value leave the maximum diameter unresolved. Pureon DP sheet, April 16, 2024

The following distinctions are explanatory synthesis of the powder, suspension and cutting-tool sources. A shared diamond identity does not make the supplied forms interchangeable. Pureon; SPLENDIS; Sumitomo.

Sumitomo's historical SUMIDIA Binderless catalog illustrates a conventional PCD structure with cobalt binder and a separate binderless material with directly bonded diamond grains of 30–50 nm. Those are cutting-tool materials. Its hardness chart uses a 4.9 N Knoop test load. Neither the hardness comparison nor the tool examples characterize a loose powder. Sumitomo, catalog pages M39–M41.

Supplier identity and fracture claims

Pureon describes DP self-sharpening through crystallite breakout under load. Its no-cleavage description concerns the aggregate. As explanatory synthesis, constituent crystals do not thereby lose their crystallographic properties. DP sheet.

EID separately lists EDD-UM premium and EDD-X-UM standard polycrystalline micron powders. Its chart spells the standard grade EDDX-UM, while the text uses EDD-X-UM. That naming difference remains unresolved here. The page describes shock synthesis, controlled microfracture and resistance to major cleavage fractures. Resistance to a fracture mode is different from immunity to fracture. EID's page gives no comparative test method, workpiece, load history or uncertainty for its pressure advantage claim. EID product page, undated.

These descriptions concern the named suppliers' materials. They do not establish one production route, binder content or fracture response for every product called polycrystalline diamond. Aggregate breakup, fracture within a crystal and separation of loosely grouped particles describe different events. This is explanatory synthesis of the stated material forms and fracture descriptions. EID; Sumitomo.

The reviewed commercial claims do not establish a universal ranking of monocrystalline and polycrystalline abrasives for cutting rate, finish or service life. A comparison without matched grain distributions, workpiece, carrier, contact conditions and endpoint leaves those influences unresolved. This is an evidence limitation, not a comparative performance result.

Grade names and particle-size distributions

Selected DP precision-range entries, in micrometers, follow. DP sheet, page 2.

No instrument or distribution weighting is specified. Grade names are not absolute size bounds. DP sheet.

As mathematical synthesis, D50 and D99 are percentile positions on the applicable cumulative distribution. They are not necessarily number percentiles. A D99 is not a zero-oversize guarantee. Median tolerance describes allowable variation in the median, rather than the spread of every particle in one lot. Neither percentile measures workpiece surface roughness.

ISO 6106:2013 addresses superabrasive grain-size checking through sieving and excludes coating from the checked grain size. Its public scope does not establish a correspondence for every submicron supplier grade. ISO public preview. FEPA distinguishes F grades for bonded conventional abrasives, P grades for coated abrasives and diamond grades prefixed D. Its cross-system comparison is approximate. A D designation, mesh designation and supplier micron label therefore require their own grading basis. FEPA grains reference.

Particle and crystallite measurements in an original study

Osipov and colleagues studied Microdiamant DP 0–0.05 as a precursor for fluorescent nanodiamonds, not as a polishing trial. Differential centrifugal sedimentation gave a distribution maximum near 27 nm and a full width at half maximum near 25 nm. HRTEM showed 5–12 nm crystallites in one illustrated polycrystal. XRD gave a 6.7 nm coherent scattering region, after instrument-response correction using a LaB₆ reference. These are distinct measurements. 2020 study, methods, figures 2–4 and note 1.

The same study detected graphite and trace elements in its precursor. Those historical sample findings are not a present DP purity specification. Its later ethanol-assisted HPHT treatment produced a separate sample, D19. The experiment characterized structure and optical defects, with no abrasive workpiece, pad or bond comparison. It supplies no removal-rate, scratch-depth or loose-grain operating-temperature limit. Osipov et al..

As synthesis, 0.025 µm = 25 nm converts length units only. It does not equate a sedimentation diameter, an imaged crystallite and a diffraction coherence length. Nanometer-sized polycrystalline particles also need not be single primary nanocrystals. The word nanodiamond alone leaves that structural distinction unresolved.

Powder mass, coatings and formulated products

Pureon's SPLENDIS O/P uses DP powder in an oil-based carrier. SPLENDIS W/P uses DP in a water-based carrier. The 2023 product-range sheet assigns W/P a pH of 8.5. These are suspension properties, not dry-grain properties. The sheet supplies no diamond mass fraction or complete ingredient list. Its application language does not qualify every polycrystalline powder for those carriers or workpieces. SPLENDIS sheet, May 24, 2023.

The following quantity relationships are explanatory synthesis. Diamond mass fraction is diamond mass divided by total supplied-product mass. A coating percentage requires its own denominator, such as coating mass divided by coated-grain mass. Powder purity and coating fractions alone do not determine mass-based diamond concentration after separate slurry formulation or dilution. For a supplied ready-to-use suspension used unchanged, its diamond mass fraction is the final slurry's mass-based diamond concentration. Material density, loose-powder bulk density and suspension density also measure different things. Interparticle voids belong to the powder-volume basis, while the suspension includes liquid.

For a hypothetical formulation containing exactly 10 wt% diamond, 200 g contains 20 g diamond. That arithmetic assumes the percentage refers to total formulation mass. It establishes no usable dilution or polishing recipe. A volume percentage cannot replace the mass percentage without the relevant density information.

The reviewed sources establish no universal coating content, residual-metal ceiling or absence of binders for loose polycrystalline powders. A binderless cutting-tool description cannot supply those missing powder specifications. No exact-grade safety sheet or lot certificate was evaluated here.

Source versions and coverage limits

The complete two-page DP sheet and four-page SPLENDIS sheet were reviewed, including tables and non-binding-information footers. Their document identifiers end in 2024-04-16 – 04.01 and 2023-05-24 – 02.07, respectively. These are the inspected editions, not proof of the latest supplier specification. DP; SPLENDIS.

EID's product page has no technical revision date. Sumitomo's three-page extract is hosted in a 2015–2016 catalog directory. Its cutting examples remain outside this powder reference's performance scope. ISO coverage is the public 2013 preview, not the full paid standard. FEPA's public page refers to historical standard editions. No standards compliance is established here. EID; Sumitomo; ISO; FEPA.

Osipov et al. appeared November 9, 2020 in Nanoscale Research Letters 15, article 209. Its structural findings retain their sample and measurement context. None of these references establishes customer capability, qualified workpiece compatibility or production settings. Original study. Finishing process references.