Polycrystalline Diamond Polishing
PACE Technologies' polycrystalline diamond polishing abrasives are designed for rapid material removal with minimal surface damage. Featuring a multi-faceted crystal structure, these abrasives enhance surface leveling and reduce sub-surface deformation, making them ideal for polishing hard and brittle materials. Compatible with a wide range of polishing cloths and lubricants, polycrystalline diamond provides superior performance in both intermediate and final polishing stages.
Key Tips for Diamond Polishing
- Select Appropriate Viscosity: Use high-viscosity suspensions for aggressive polishing, and low-viscosity for delicate or heat-sensitive materials.
- Pair with Compatible Pads: Use low-nap or non-woven polishing pads to optimize abrasive contact and surface finish.
- Adjust Force and Time: Polycrystalline diamond cuts faster, so reduce polishing time and pressure to prevent over-polishing or relief.
- Clean Between Steps: Prevent cross-contamination by thoroughly cleaning specimens, pads, and platens between polishing stages.
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Introduction
Polycrystalline diamond polishing is a critical step in achieving uniform, high-quality surface finishes during metallographic sample preparation. With its multi-faceted crystal structure, polycrystalline diamond offers superior material removal rates and minimized subsurface damage, especially on hard and brittle materials. These abrasives are best used with low- to medium-napped polishing pads to maintain flatness and avoid issues like relief or edge rounding. Selecting the proper viscosity and suspension format—paired with the right cloth and lubrication—ensures efficient, reproducible polishing results for accurate microstructural analysis.
Diamond Abrasive Selection Guidelines
This reference outlines best-practice abrasive sizes for rough and final polishing across metals, ceramics, and composite materials. Proper abrasive selection is critical to ensure accurate microstructural representation, prevent surface damage, and optimize polishing efficiency.
Preferred Abrasive
Acceptable Alternative
Not Typically Recommended
Polishing Guide for Metals
| Metal | Rough Polishing (Diamond) | Final Polishing (Oxide) | ||||
|---|---|---|---|---|---|---|
| Abrasive Size | 9 µm | 6 µm | 3 µm | 1 µm | Al2O3 | SiO2 |
| Aluminum | ||||||
| Copper / Brass | ||||||
| Stainless Steel | ||||||
| Soft Steel | ||||||
| Hard Steel | ||||||
| Tool Steel | ||||||
| Titanium | Etch Polish | |||||
| Zinc, Tin, Lead | ||||||
Polishing Guide for Ceramics and Composites
| Ceramic / Composite | Coarse Grind | Fine Grind | Rough Polish | Fine Polish | ||
|---|---|---|---|---|---|---|
| Diamond Size | 30 µm | 15 µm | 9 µm | 6 µm | 3 µm | 1 µm + SiO2 |
| Alumina | ||||||
| Silicon Nitride | ||||||
| Polymer Composite | ||||||
| Metal Matrix Composite | ||||||
| Ceramic Matrix Composite | ||||||
| Cermet | ||||||
Note: These selections reflect proven laboratory procedures balancing speed, flatness, and structure preservation. Adjust abrasive types and sequence for material-specific variables such as grain size, hardness, and thermal sensitivity.
Polishing Pad Selection Guideline
| Pad Image & Link | Use Case | Pad Icon | Polishing Stage |
|---|---|---|---|
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CERMESH metal mesh pad used for semi-fixed abrasive coarse to intermediate lapping. Excellent for initial removal of damage from sectioning and hard materials. |
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Coarse / Intermediate |
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POLYPAD is a durable synthetic polyester pad ideal for intermediate polishing, especially with 6–15 µm diamond abrasives. Designed as a long-life nylon alternative. |
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Intermediate |
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TEXPAN is a widely used non-woven intermediate polishing pad, compatible with most diamond suspensions. Effective across a broad range of materials. |
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Intermediate |
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Black CHEM 2 is a porometric polymer pad with rubber-like consistency, offering balanced action between low and high nap pads. Ideal for moderate nap intermediate polishing. |
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Intermediate |
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DACRON II is a low-napped soft polishing pad widely used in Europe for intermediate steps on metals. Suitable for 1–15 µm diamond abrasives. |
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Intermediate |
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NYPAD is a low-napped silk pad tailored for intermediate polishing of harder metals and alloys. Performs well with mid-size diamond abrasives. |
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Intermediate |
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GOLD PAD is a low-napped pad ideal for 1–9 µm polishing. Designed for consistent material removal and flatness control during final pre-polishing. |
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Intermediate |
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ATLANTIS is a woven low-nap final polishing pad with foam backing for enhanced compliance. Ideal for 1–6 µm diamond. Great for critical surface flatness needs. |
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Final |
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MICROPAD is a high-napped final polishing pad ideal for producing a mirror finish on metals and polymers. Recommended for <1 µm diamond or colloidal silica. |
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Final |
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TRICOTE is a tight high-napped final polishing pad for metals. Offers better control of surface texture and minimal abrasive drag. |
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Final |
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NAPPAD is a very high-napped final polishing pad tailored for soft metals and polymers. Provides gentle polishing action to minimize pull-out and relief. |
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Final |
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MOLTEC 2 is a wool-based final polishing cloth used when edge retention is not critical. Works well with alumina and colloidal silica on metals. |
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Final |
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FELT PAD is a thick final polishing pad made for large samples or glass. Ideal for use with colloidal silica or alumina slurries where surface uniformity is key. |
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Final |
Shop Polishing Pads / Cloths
Process Description
Polycrystalline diamond polishing is typically performed in one or two stages depending on material hardness and surface condition. For rough polishing, low- to medium-napped pads are used with coarse polycrystalline diamond suspensions or pastes to efficiently remove grinding damage. In many cases, this may be followed by a finer grade of polycrystalline diamond for surface refinement. Due to the abrasive’s multi-crystalline nature, material removal is rapid yet controlled, minimizing heat and deformation. Excessive polishing should be avoided to prevent artifacts such as relief, smear, or rounding.
Minimizing Polishing Artifacts
To prevent common polishing issues such as edge rounding, relief, or abrasive embedding:
- Use polycrystalline diamond suspensions with the correct viscosity for your application
- Select low-napped pads to maintain surface flatness during rough polishing
- Ensure polishing plates have minimal runout (≤2.5 µm for 8" platens)
- Use moderate force and avoid prolonged polishing times
Recommended Procedures
- Secure the polishing pad firmly to a flat platen (adhesive or magnetic backing as appropriate)
- Pre-wet and pre-charge the pad with polycrystalline diamond suspension or paste
- Apply the recommended lubricant to optimize cutting and prevent pad clogging
- Start polishing with reduced downforce to avoid premature pad wear or sample relief
- Rinse specimen and pad with water or ethanol during the final 10–15 seconds of polishing
- Clean and dry specimens thoroughly to remove all residues before inspection
Troubleshooting
| Symptom | Cause | Solution |
|---|---|---|
| Coarse Scratching | Contaminated polishing pad or incorrect pad pairing | Replace pad; use correct pad type for polycrystalline diamond |
| Agglomerated Diamond | Pre-mixing with colloidal silica; bacterial growth in suspension | Dispense abrasives separately; replace suspension if contaminated |
| Uneven Polishing | Worn pad or uneven platen surface | Replace pad; check and resurface platen if needed |
| Edge Rounding / Excessive Relief | Too much downforce or extended polishing duration | Reduce force; shorten polishing time; verify prior steps were sufficient |
| Low Polishing Rate | Insufficient abrasive concentration or poor pad saturation | Increase suspension application rate; recharge pad with diamond |
| Tearing of Pad | High pressure or inadequate lubrication | Lower pressure; apply lubricant more frequently |
| Specimen Smear or Pull-Out | Inappropriate pad or overly aggressive abrasive size | Use lower nap pad and finer diamond grit; evaluate pad compatibility |
Polycrystalline Diamond Suspensions (water-based)
| Description | Quantity | Low Viscosity | High Viscosity | Product Image |
|---|---|---|---|---|
| 0.05 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-0105-250 GPC-0105-500 GPC-0105-1GL |
PC-0105-250 PC-0105-500 PC-0105-1GH |
 |
| 0.1 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-0110-250 GPC-0110-500 GPC-0110-1GL |
PC-0110-250 PC-0110-500 PC-0110-1GH |
 |
| 0.25 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-0125-250 GPC-0125-500 GPC-0125-1GL |
PC-0125-250 PC-0125-500 PC-0125-1GH |
 |
| 0.5 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-0150-250 GPC-0150-500 GPC-0150-1GL |
PC-0150-250 PC-0150-500 PC-0150-1GH |
 |
| 1 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1001-250 GPC-1001-500 GPC-1001-1GL |
PC-1001-250 PC-1001-500 PC-1001-1GH |
 |
| 3 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1003-250 GPC-1003-500 GPC-1003-1GL |
PC-1003-250 PC-1003-500 PC-1003-1GH |
 |
| 6 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1006-250 GPC-1006-500 GPC-1006-1GL |
PC-1006-250 PC-1006-500 PC-1006-1GH |
 |
| 9 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1009-250 GPC-1009-500 GPC-1009-1GL |
PC-1009-250 PC-1009-500 PC-1009-1GH |
 |
| 15 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1015-250 GPC-1015-500 GPC-1015-1GL |
PC-1015-250 PC-1015-500 PC-1015-1GH |
 |
| 30 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1030-250 GPC-1030-500 GPC-1030-1GL |
PC-1030-250 PC-1030-500 PC-1030-1GH |
 |
| 45 micron DIAMAT Polycrystalline diamond | 250 ml 500 ml 1 gallon |
GPC-1045-250 GPC-1045-500 GPC-1045-1GL |
PC-1045-250 PC-1045-500 PC-1045-1GH |
 |
Polycrystalline Diamond Suspension – Dyed
| Description | Quantity | Catalog Number | Product Image |
|---|---|---|---|
| 1 micron (blue) DIAMAT PC Suspension | 1 liter | PC-1001-1L |  |
| 1 micron (blue) DIAMAT PC Suspension | 1 gallon | PC-1001-1GLB | |
| 3 micron (green) DIAMAT PC Suspension | 1 liter | PC-1003-1L |  |
| 3 micron (green) DIAMAT PC Suspension | 1 gallon | PC-1003-1GLG | |
| 6 micron (yellow) DIAMAT PC Suspension | 1 liter | PC-1006-1L |  |
| 6 micron (yellow) DIAMAT PC Suspension | 1 gallon | PC-1006-1GLY | |
| 9 micron (red) DIAMAT PC Suspension | 1 liter | PC-1009-1L |  |
| 9 micron (red) DIAMAT PC Suspension | 1 gallon | PC-1009-1GLR | |
| 15 micron (brown) DIAMAT PC Suspension | 1 liter | PC-1015-1L |  |
| 15 micron (brown) DIAMAT PC Suspension | 1 gallon | PC-1015-1GLBR | |
| 30 micron (orange) DIAMAT PC Suspension | 1 liter | PC-1030-1L |  |
| 30 micron (orange) DIAMAT PC Suspension | 1 gallon | PC-1030-1GLO | |
| 45 micron (purple) DIAMAT PC Suspension | 1 liter | PC-1045-1L |  |
| 45 micron (purple) DIAMAT PC Suspension | 1 gallon | PC-1045-1GLP |
Polycrystalline Diamond Paste
| Description | Quantity | Catalog Number | Product Image |
|---|---|---|---|
| DIAMAT Polycrystalline Diamond Paste (0.1 µm) | 5 gm 20 gm |
PC-0210-05 PC-0210-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (0.25 µm) | 5 gm 20 gm |
PC-0225-05 PC-0225-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (0.5 µm) | 5 gm 20 gm |
PC-0250-05 PC-0250-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (1 µm) | 5 gm 20 gm |
PC-2001-05 PC-2001-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (3 µm) | 5 gm 20 gm |
PC-2003-05 PC-2003-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (6 µm) | 5 gm 20 gm |
PC-2006-05 PC-2006-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (9 µm) | 5 gm 20 gm |
PC-2009-05 PC-2009-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (15 µm) | 5 gm 20 gm |
PC-2015-05 PC-2015-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (30 µm) | 5 gm 20 gm |
PC-2030-05 PC-2030-20 |
 |
| DIAMAT Polycrystalline Diamond Paste (45 µm) | 5 gm 20 gm |
PC-2045-05 PC-2045-20 |
 |
Diamond Extenders (Lubricants)
| Description | Quantity | Catalog Number | Product Image |
|---|---|---|---|
| DIALUBE Diamond Extender | 16 oz (0.125L) 32 oz (0.24L) 1 gallon (3.8L) |
DL-3000-16 DL-3000-32 DL-3000-128 |
|
| DIALUBE Blue Alcohol Lubricant | 16 oz (0.125L) 32 oz (0.24L) 1 gallon (3.8L) |
AOD-3000-16 AOD-3000-32 AOD-3000-128 |
|
| DIALUBE Purple Alcohol Lubricant | 16 oz (0.125L) 32 oz (0.24L) 1 gallon (3.8L) |
ADL-3000-16 ADL-3000-32 ADL-3000-128 |
|
| POLYLUBE Non-Aqueous Diamond Extender | 16 oz (0.125L) 32 oz (0.24L) 1 gallon (3.8L) |
PDL-3000-16 PDL-3000-32 PDL-3000-128 |
|
| POLYLUBE Red (Anti-Corrosion) Lube | 16 oz (0.125L) 32 oz (0.24L) 1 gallon (3.8L) |
PDL-3000R-16 PDL-3000R-32 PDL-3000R-128 |