Can diamond be used as an abrasive?
Conclusion:
- Diamond is currently the most important and hardest superhard abrasive used in industry; however, it has specific application limits and is not suitable for all materials.
Metal Bond Diamond Fickert Abrasive is used for grinding stone.
I. Why diamond is suitable as an abrasive:
Diamond is the hardest known substance in nature, with a microhardness far exceeding that of common abrasives like corundum and silicon carbide.
- Exceptional cutting ability, low grinding resistance, and high processing efficiency;
- Excellent wear resistance; under identical processing conditions, tool service life is far longer than that of tools using common abrasives;
- Available in various forms-such as single-crystal particles, micropowders, and polycrystalline aggregates-making it compatible with sintered, electroplated, brazed, and resin-bonded diamond tools;
- Comprehensive grit size range, covering everything from coarse cutting and rough grinding to ultra-fine powder polishing.
Common diamond abrasive products:
- Metal-bonded grinding blocks, resin-bonded grinding discs, saw blades, core drill bits, electroplated grinding wheels, flexible polishing pads, tumbling media, etc.
II. Key usage restriction (Important):
Diamond must not be used to grind iron-group metals (carbon steel, stainless steel, mold steel, cast iron).
During high-temperature grinding, the diamond (primarily composed of carbon) undergoes a solid-state reaction with iron:
- Fe + C -> Cementite + Graphitization
- The diamond surface rapidly graphitizes and loses hardness, leading to quick dulling and wear.
- For processing steel, the standard choice is CBN (Cubic Boron Nitride), not diamond.
✅ Diamond abrasives are suitable for processing (non-metallic and non-iron-based hard materials):
Natural marble, granite, luxury stone, slate, concrete, glass, ceramics, cemented carbide, graphite, jade, refractory materials, sintered stone slabs, etc.
❌ Not suitable for:
Various types of steel, stainless steel, nickel-based alloys, and other iron-group metals.
(Grinding wheels with CBN as abrasive are often used to process workpieces made of steel materials)
III. Distinction Between Two Major Categories of Diamond Abrasives
1 Synthetic Monocrystalline Diamond Abrasives (Industry Standard)
- Characterized by sharp, angular grains that enable rapid cutting; widely used in stone grinding blocks, drill bits, and cutting blades. Can undergo titanium coating to enhance retention within the metal bond matrix.
2 Polycrystalline Diamond (PCD) Micropowder
- Isotropic in nature, making it resistant to directional fracturing; primarily used for high-precision polishing and dressing tools.
IV. Brief Comparison with Conventional Abrasives (e.g., Brown Fused Alumina, Silicon Carbide)
- Conventional abrasives: Lower hardness, suitable for grinding metals; prone to rapid wear, resulting in very low efficiency when processing hard stone.
- Diamond superhard abrasives: Specialized for hard non-metallic materials; offers superior hardness but suffers from a drawback known as "iron affinity" (chemical reactivity with iron).
Summary:
Diamond is a premier superhard abrasive widely used in processing stone, concrete, and ceramics; however, due to chemical compatibility limitations, it is strictly unsuitable for grinding steel. Diamond abrasives offer irreplaceable advantages when processing hard, non-ferrous materials.