Black SiC and Green SiC are both hard and tough abrasion materials in the industrial field. Besides the color difference, there are many differences in properties and performance.
The following aspects are the main differences:
1. The production process difference.
Black SiC (Black carborundum) is made of quartz sand, petroleum coke, and high-quality silica as raw materials, and is smelted through a resistance furnace at high temperature. Some black silicon carbide manufacturers adopt anthracite to replace petroleum to save cost.
Green SiC (Green carborundum) is made from petroleum coke and high-quality silica as the main raw materials in a similar smelting process. But it added salt as an additive to make green color.
2. Differences in physical and chemical properties.
Black silicon carbide has a hardness between corundum and diamond, higher mechanical strength than corundum, and is brittle and sharp. The green carborundum is harder than the black one. There are details as follows:
| Index | Black SiC(A grade) | Green SiC |
| Chemical composition | SiC:98-99.2% | SiC 98.8-99.5% |
| Mohs Hardness: | 9.2-9.3 | 9.4-9.5 |
| Vicker hardness: | 28-32 GPa | 33-34 GPa |
| Specific Gravity: | 3.15-3.20 g/cm3 | 3.2-3.45 g/cm3 |
| Bulk density(LPD depends on the size): | 0.8-1.5 g/cm3 | 0.6-1.5 g/cm3 |
| Color: | Black | Green |
| Particle shape: | Hexagonal | Hexagonal |
| Modulus of Elasticity | 58-65×106 psi | 58-65×106 psi |
| Coefficient of Thermal Expansion | 3.9-4.5 x10-6 /°C | 4.0-4.8 x10-6 /°C |
| Thermal Conductivity (at 25°C) | 70-130 W/M·K | 60-200W/M·K |
| Raw material | Petroleum coke, quartz sand | Petroleum coke,quartz sand,Salt |
| Available Specifications | F12-F220,F230-F1200,P40-P5000 | F12-F220,F230-F2000 |
3. Differences in purpose:
》》Grinding industry: Black silicon carbide is used for grinding alloys, ceramics, marble, and jade materials. Green silicon carbide is commonly used for grinding materials such as hard alloys, quartz glass, optical glass, granite, etc. Green silicon carbide is also a commonly used material for crystal wire cutting.
》》Silicon carbide ceramics industry: black silicon carbide is used for DPF particle filters, silicon carbide pump bodies, foam ceramics, etc. Green silicon carbide is used for reaction sintering of silicon carbide ceramics, such as silicon carbide nozzles, silicon carbide rollers, bulletproof ceramics, etc.
》》Abrasive industry: Black silicon carbide is used in fields such as water abrasive paper and coated abrasives. Green silicon carbide is used in fields such as diamond grinding wheel accessories, stone grinding discs, PVA grinding wheels, and diamond clay grinding blocks.
》》Other industries: Typical uses of black silicon carbide include refractory mastic, filling desulfurization systems in power plants, and so on. Low-grade silicon carbide (containing about 85% SiC) is an excellent deoxidizer, which can accelerate steelmaking speed, facilitate chemical composition control, and improve steel quality. Typical applications of green silicon carbide include non-stick pan coating (PTFE), nano aerogel gel additive materials, and other fields.
In sum, green SiC has a better performance than Black SiC, but Black SiC has the advantage in price. Thus, users could choose the proper one with different quality requirements.
