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Monocrystalline Diamond Polishing

PACE Technologies' monocrystalline diamond polishing abrasives deliver sharp, angular cutting action for high-efficiency material removal in metallographic sample preparation. These single-crystal abrasives are best suited for applications requiring aggressive polishing and long abrasive life.

Monocrystalline Diamond Polishing

Key Considerations

Choose the Right Viscosity

High-viscosity for rapid removal; low-viscosity for fine control or sensitive samples.

Use Compatible Pads

Pair with low-nap or resilient pads for optimal flatness and abrasive efficiency.

Control Force and Duration

Monocrystalline diamond is aggressive: use moderate pressure and shorter cycles.

Introduction

Monocrystalline diamond polishing plays a vital role in producing sharp, high-resolution surface finishes in metallographic sample preparation. Composed of single-crystal diamond particles, these abrasives exhibit angular, blocky shapes that deliver fast, aggressive cutting action--ideal for metals and harder materials. Monocrystalline diamond is best used with resilient, low- to medium-napped polishing pads to maintain planarity and minimize smearing. Proper selection of abrasive size, suspension medium, and compatible lubrication ensures precise, efficient polishing with consistent material removal and excellent edge retention.

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
CERMESH CERMESH metal mesh pad used for semi-fixed abrasive coarse to intermediate lapping. Excellent for initial removal of damage from sectioning and hard materials. CERMESH icon Coarse / Intermediate
POLYPAD 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. POLYPAD icon Intermediate
TEXPAN TEXPAN is a widely used non-woven intermediate polishing pad, compatible with most diamond suspensions. Effective across a broad range of materials. TEXPAN icon Intermediate
Black CHEM 2 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. Black CHEM 2 icon Intermediate
DACRON II 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. DACRON icon Intermediate
NYPAD NYPAD is a low-napped silk pad tailored for intermediate polishing of harder metals and alloys. Performs well with mid-size diamond abrasives. NYPAD icon Intermediate
GOLD PAD 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. GOLD PAD icon Intermediate
ATLANTIS 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. ATLANTIS icon Final
MICROPAD 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. MICROPAD icon Final
TRICOTE TRICOTE is a tight high-napped final polishing pad for metals. Offers better control of surface texture and minimal abrasive drag. TRICOTE icon Final
NAPPAD 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. NAPPAD icon Final
MOLTEC 2 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. MOLTEC icon Final
FELT PAD 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. FELT PAD icon Final
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Process Description

Monocrystalline diamond polishing is commonly used in one or more stages to remove grinding damage and achieve smooth, reflective surfaces on metals and hard materials. The sharp, angular particles of monocrystalline diamond provide aggressive cutting, making it ideal for high-efficiency rough and intermediate polishing. Use coarser grades for initial steps, followed by finer grades to refine the surface. To avoid surface damage, polishing time and pressure should be carefully controlled.

Minimizing Polishing Artifacts

To reduce edge rounding, relief, and embedding during monocrystalline diamond polishing:

  • Choose the correct abrasive size and viscosity for the material and stage
  • Use low-nap or non-woven pads to support flat, uniform surfaces
  • Ensure platens are flat and runout is under 2.5 µm (for 8" discs)
  • Apply even pressure and limit polishing durations to avoid over-polishing
Consistent preparation practices and a well-maintained polishing surface are key to reproducible results.

Recommended Procedures

  • Secure the polishing pad firmly onto a flat, clean platen
  • Apply several beads of monocrystalline diamond suspension or extender to initiate pad wetting. Avoid full saturation.
  • Dispense additional diamond at a rate of 1-2 drops every 10-15 seconds during polishing, depending on speed and sample area
  • Introduce a compatible lubricant to reduce heat and optimize abrasive performance
  • For ceramic and mineral specimens, alternate diamond and colloidal silica (e.g., SIAMAT) for enhanced chemomechanical polishing (CMP)
  • Begin polishing with moderate force to leverage the sharp, angular cutting action of monocrystalline diamond
  • During the final 15 seconds of the cycle, flush the pad and specimen with water to remove residue and condition the surface
  • After polishing, rinse specimens thoroughly and dry completely before microscopic inspection

Monocrystalline Diamond Suspensions (water-based)

Description Quantity Low Viscosity High Viscosity Product Image
1 micron (blue) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1001-250
GMA-1001-500
GMA-1001-1GL
MA-1001-250
MA-1001-500
MA-1001-1GL
PACE Technologies 1 micron monocrystalline diamond suspension
3 micron (green) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1003-250
GMA-1003-500
GMA-1003-1GL
MA-1003-250
MA-1003-500
MA-1003-1GL
PACE Technologies 3 micron monocrystalline diamond suspension
6 micron (yellow) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1006-250
GMA-1006-500
GMA-1006-1GL
MA-1006-250
MA-1006-500
MA-1006-1GL
PACE Technologies 6 micron monocrystalline diamond suspension
9 micron (red) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1009-250
GMA-1009-500
GMA-1009-1GL
MA-1009-250
MA-1009-500
MA-1009-1GL
PACE Technologies 9 micron monocrystalline diamond suspension
15 micron (brown) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1015-250
GMA-1015-500
GMA-1015-1GL
MA-1015-250
MA-1015-500
MA-1015-1GL
PACE Technologies 15 micron monocrystalline diamond suspension
30 micron (orange) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1030-250
GMA-1030-500
GMA-1030-1GL
MA-1030-250
MA-1030-500
MA-1030-1GL
PACE Technologies 30 micron monocrystalline diamond suspension
45 micron (purple) DIAMAT Monocrystalline diamond 250 ml
500 ml
1 gallon
GMA-1045-250
GMA-1045-500
GMA-1045-1GL
MA-1045-250
MA-1045-500
MA-1045-1GL
PACE Technologies 45 micron monocrystalline diamond suspension

Monocrystalline Diamond Paste

Description Quantity Catalog Number Product Image
DIAMAT Monocrystalline diamond paste (0.25 micron) 5 gm
20 gm
MA-0225-05
MA-0225-20
PACE Technologies 0.25 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (0.50 micron) 5 gm
20 gm
MA-0250-05
MA-0250-20
PACE Technologies 0.50 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (1 micron) 5 gm
20 gm
MA-2001-05
MA-2001-20
PACE Technologies 1 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (3 micron) 5 gm
20 gm
MA-2003-05
MA-2003-20
PACE Technologies 3 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (6 micron) 5 gm
20 gm
MA-2006-05
MA-2006-20
PACE Technologies 6 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (9 micron) 5 gm
20 gm
MA-2009-05
MA-2009-20
PACE Technologies 9 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (15 micron) 5 gm
20 gm
MA-2015-05
MA-2015-20
PACE Technologies 15 micron monocrystalline diamond paste
DIAMAT Monocrystalline diamond paste (30 micron) 5 gm
20 gm
MA-2030-05
MA-2030-20
PACE Technologies 30 micron monocrystalline diamond paste

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
Metallographic diamond polishing lubricants
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

Troubleshooting

Symptom Cause Solution
Coarse Scratching Old or contaminated suspension; excessive abrasive pressure Use fresh monocrystalline suspension; reduce applied force
Uneven Material Removal Poor abrasive distribution or inconsistent pad contact Ensure even application of suspension; verify flat, stable platen setup
Pad Glazing Diamond buildup or insufficient flushing Flush regularly with water or alcohol; condition or replace pad
Edge Rounding Over-polishing or inappropriate pad compliance Reduce polishing time; use a firmer pad to maintain edge definition
Low Material Removal Rate Low abrasive loading or degraded diamond suspension Reapply suspension more frequently; check expiration of abrasive
Specimen Drag or Pad Tearing Insufficient lubrication with high downforce Increase lubricant volume; reduce pressure
Surface Smearing or Pull-Out Overly aggressive grit size for specimen material Switch to finer monocrystalline grit; ensure pad matches application

Related Equipment

Frequently Asked Questions

Common questions about monocrystalline diamond polishing

What is the difference between monocrystalline and polycrystalline diamond?

Monocrystalline diamond consists of single-crystal particles with uniform, blocky geometry, providing sharp cutting edges and consistent polishing performance. Polycrystalline diamond has multiple crystal structures with irregular shapes, offering aggressive cutting for rapid material removal. Monocrystalline is preferred for controlled, fine polishing and superior surface finish, while polycrystalline excels at rough polishing of hard materials.

Which materials benefit most from monocrystalline diamond polishing?

Monocrystalline diamond is ideal for metals requiring high-quality surface finish including stainless steel, tool steel, hard steel, and precious metals. It's also excellent for ceramics, semiconductors, and composite materials where fine polishing and minimal surface damage are critical. For very hard materials like carbides, monocrystalline provides better control and less aggressive cutting compared to polycrystalline diamond.

What is the best particle size for final polishing with monocrystalline diamond?

For final polishing, 1 µm monocrystalline diamond is the standard choice for most metals and hard materials. For ultra-fine surfaces, 0.25-0.5 µm monocrystalline diamond provides exceptional results with minimal scratching. Always follow diamond polishing with a colloidal silica or alumina final step for the best microstructural revelation and surface quality.

Should I use low-viscosity or high-viscosity monocrystalline diamond?

Low-viscosity suspensions (DIAMAT GMA series) provide excellent heat dissipation and uniform abrasive distribution, ideal for automated polishing and extended polishing cycles. High-viscosity suspensions and pastes (DIAMAT MA series) offer concentrated abrasive delivery and longer working time, preferred for manual polishing or when frequent reapplication is impractical. Choose based on your equipment, material, and workflow preferences.

How do I prevent edge rounding with monocrystalline diamond polishing?

To minimize edge rounding, use low-nap or non-woven polishing pads that provide firm support. Reduce polishing time and pressure, especially with finer diamond grades. Ensure your platen is perfectly flat with minimal runout. Consider using rigid composite pads or magnetic polishing systems for critical edge retention. Inspect samples frequently and stop polishing as soon as the desired surface finish is achieved.

Can I use monocrystalline diamond on soft metals like aluminum and copper?

Yes, monocrystalline diamond works well on soft, ductile metals when used with fine particle sizes (1-3 µm) and appropriate techniques. Use low pressure, short polishing times, and low-nap pads to prevent smearing and relief. For aluminum and copper alloys, start with 3 µm monocrystalline, then finish with 1 µm diamond followed by colloidal silica for optimal results. Avoid coarse diamond grades that can cause excessive material removal and surface damage.

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