Black silicon carbide can effectively improve the surface cleanliness of workpieces, but its cutting performance may decrease under certain conditions. When exposed to temperatures above a certain limit, black silicon carbide is prone to oxidation. However, the oxidation process also forms a protective layer that helps maintain its chemical stability.
Chemical Stability of Black Silicon Carbide
Black silicon carbide is prone to oxidation at temperatures above 1,000°C. During oxidation, however, a thin layer of silicon dioxide (SiO₂) forms on the surface and covers the silicon carbide. This protective film significantly slows further oxidation, allowing silicon carbide products to remain stable during long-term use at temperatures of up to approximately 1,600°C.
The high-temperature behavior of black silicon carbide is somewhat similar to that of aluminum at room temperature. In both cases, valuable engineering properties are closely related to the high chemical stability of the protective oxide film. Within its appropriate operating temperature range, black silicon carbide maintains good chemical stability and wear resistance, which helps extend its service life.
Cutting Performance of Black Silicon Carbide
Fracturing of black silicon carbide reduces the number of larger abrasive grains capable of effective cutting. The smaller grains produced by fracture can also become clogged with chips, preventing them from continuing to perform an effective cutting action.
However, before fracturing, the sharp edges of the abrasive grains may not have become significantly dull. Therefore, their cutting ability is not necessarily lost completely; instead, the grain size becomes somewhat smaller. At the same time, an excessively coarse grit can also reduce cutting performance because larger grains are more prone to fracture.
To reduce unnecessary grain fracture, grit selection should take several factors into account, including the grinding capability required, the hardness of the abrasive tool, and the properties of the workpiece material. Matching these factors properly can help minimize grain fracture and maintain more consistent cutting performance.
