What is Green Silicon Carbide?
Green silicon carbide (SiC) is a synthetic, high-purity abrasive. It is produced in a high-temperature electric resistance furnace from a mixture of silica sand and petroleum coke, with salt as a reactant. Its green color and higher purity distinguish it from the more common black silicon carbide, which contains more impurities.
| TYPICAL CHEMICAL ANALYSIS | |
| SiC | ≥99.05% |
| SiO2 | ≤0.20% |
| F,Si | ≤0.03% |
| Fe2O3 | ≤0.10% |
| F.C | ≤0.04% |
| TYPICAL PHISICAL PROPERTIES | |
| Hardness: | Mohs：9.5 |
| Melting Point: | Sublimes at 2600 ℃ |
| Maximum service temperature: | 1900℃ |
| Specific Gravity: | 3.20-3.25g/cm3 |
| Bulk density(LPD): | 1.2-1.6 g/cm3 |
| Color: | Green |
| Particle shape: | Hexagonal |
| Size： | |
| Micropowder： JIS:240# 280# 320# 360# 400# 500# 600# 700# 800# 1000# 1200# 1500# 2000# 2500# 3000# 4000# 6000# 8000# 10000# FEPA： F230 F240 F320 F360 F400 F500 F600 F800 F1000 F1200 F1500 F2000 | |
In the world of sharpening, it is a premier material for certain types of whetstones, prized for its extreme hardness and sharp, brittle crystals.
Green Silicon Carbide Properties for Whetstone
Exceptional Hardness: With a Mohs hardness of 9.2-9.5, it is one of the hardest abrasives available. This allows it to cut virtually all tool steels effectively.
Sharp, Brittle Crystals: The crystals have very sharp edges but are also brittle. This is a key advantage. As you use the stone, the crystals fracture, constantly revealing new, sharp cutting points. This property is known as “self-sharpening” or friability, which helps the stone resist glazing and maintain its cutting speed.
Fast Cutting Action: Due to its hardness and self-sharpening nature, green silicon carbide stones are known for their aggressive and fast material removal.
Common Forms of Green Silicon Carbide Whetstones
1. Sintered/Bonded Stones
This is the most common form. The abrasive powder is mixed with a binder (like vitrified ceramic or resin) and fired in a kiln to form a solid stone.
Vitrified Bonds: Create a hard, durable, and porous stone. They are typically used with water for lubrication and cleaning.
Resin Bonds: Create a slightly softer, more flexible stone that is less prone to loading (clogging with metal particles).
2. Lapping Powders & Compounds
The micro-powder is suspended in a carrier (grease, oil, or water) to create a lapping compound. This compound is applied to a flat surface (like a glass plate or a lapping plate) for ultra-fine polishing of edges to a mirror finish.
Ideal Uses and Target Tools
Green silicon carbide stones are exceptionally versatile but excel in specific areas:
Sharpening Hard Steels: Excellent for high-alloy tool steels, stainless steel kitchen knives, and chisels.
Sharpening Non-Ferrous Materials: This is a key strength. It is the preferred abrasive for sharpening tools made of tungsten carbide (e.g., carbide woodturning tools, router bits). While slower than a diamond plate, it is very effective.
Lapidary and Glass Work: Its hardness makes it ideal for grinding and shaping hard, non-metallic materials like glass, stone, and ceramics.
General-Purpose Sharpening: A great all-around stone for most workshop and kitchen needs.
Important Note: It is NOT suitable for sharpening ceramic knives, as ceramic is harder.
Grit Ranges and Their Applications
| Grit Range | Common Designation | Primary Use |
|---|---|---|
| Coarse | 80 – 220 grit | Repair: Fixing nicks, chips, and re-profiling badly damaged edges. Fast cutting but leaves deep scratches. |
| Medium | 320 – 600 grit | Sharpening: The workhorse range for routine sharpening, quickly establishing a new bevel and burr. |
| Fine | 800 – 1500 grit | Refining: Refining the edge from medium stones, preparing it for polishing, or creating a very sharp working edge. |
| Very Fine/Polish | 2000+ grit, W10 and finer | Polishing: Often used as a loose powder or compound to create a razor-sharp, polished (“mirror”) edge. |