Silicon Carbide (SiC) Micron Powder, Purity: 99,9%, Size: 250 µm

FAQ About Silicon Carbide (SiC) Micron Powder, 250 µm

1) What kind of grade is 250 µm silicon carbide?

This is a coarse grade. At 250 µm the particles are visible as distinct grit rather than a fine powder, which places it in the size range used for grinding, lapping, blasting media and refractory aggregate rather than for fine ceramic forming. Coarse silicon carbide removes material quickly and packs with open porosity, so it suits applications where cutting rate or bulk thermal mass matters more than surface smoothness.

2) How does this differ from the 180–250 µm graded product?

This SKU is specified as a single nominal size of 250 µm at 99.9% purity. The 180–250 µm graded grade at 99.5+% is specified as a controlled distribution between two limits, and is also stocked in 5 kg quantities. Choose the graded product when the width of the size distribution is part of your process specification; choose this one when a nominal coarse grit at higher stated purity is what the application calls for.

3) What does 99.9% purity change compared with the 99.5+% grades?

Purity in silicon carbide is mostly about residual free carbon and metallic elements carried over from synthesis. Nanografi's 99.5+% graded series publishes those residuals explicitly — free carbon at 0.05%, with aluminium, iron and calcium each below 0.06%. A higher stated purity matters where those residuals would interfere: in electronic and semiconductor-adjacent components, in high-temperature service where metallic residues flux, and wherever contamination transfers to the workpiece during abrasive use.

4) How does particle size affect abrasive performance?

Coarse particles present fewer, larger cutting points, so each one carries more load and removes material faster while leaving a rougher surface. Fine particles present many small points that cut slowly and leave a smoother finish. A 250 µm grade therefore belongs at the stock-removal end of a process sequence, with progressively finer grades used for the finishing passes. Matching grit size to the stage of the operation matters more than the absolute hardness of the abrasive.

5) Is this grade suitable for sintering structural ceramics?

Generally not. Sintering depends on high specific surface area to drive densification, and a 250 µm powder has far too little. Fine grades are the appropriate selection there — the 0.5–1 µm grade is specified with a specific surface area of 16–18 m²/g and an untreated, high-energy surface for exactly this reason. Coarse silicon carbide does appear in ceramic bodies, but as an aggregate phase within a fine matrix rather than as the sintering powder itself.

6) What material properties does silicon carbide have?

Silicon carbide is registered under CAS number 409-21-2. Across its silicon carbide micron powder range, Nanografi publishes a hardness of 9.5 Mohs, a density of 3.216 g/cm³ at 288 K and a thermal expansion coefficient of 2.98 × 10⁻⁶ at 1173 K. That combination — near-diamond hardness, low density and very low thermal expansion — is why the material serves as both an abrasive and a thermal-shock-resistant refractory, as discussed in silicon carbide micron and nano powder.

7) How should the powder be stored?

Nanografi's guidance for its silicon carbide micron powders is to keep them sealed, in a cool, dry room, protected from air exposure and from mechanical stress. Silicon carbide is chemically stable and is not a radioactive mineral, contains no heavy metals and no toxic or carcinogenic substances, but coarse grit is abrasive to skin, eyes and equipment seals. The MSDS linked on the product page states the handling and protective requirements.

8) Which applications use this grade, and what quantities are supplied?

Coarse silicon carbide is used in polishing abrasives and grinding wheels, high-grade refractory bodies and kiln furniture, high-temperature sealing valves, spray nozzles and fluid transport parts, and as a reinforcing or wear-resistant phase in composites. It is supplied in 5 g, 25 g, 100 g, 500 g and 1000 g quantities, with larger volumes quoted on request. The full size range, from sub-micron to 2000 µm, is listed under silicon carbide micron powder.