Green silicon carbide (SiC) is a superior abrasive and reinforcing material chosen for wear-resistant coatings primarily due to its exceptional hardness, outstanding wear resistance, excellent thermal stability, and good chemical inertness. It acts as the “hard skeleton” within the coating, drastically extending the life of components exposed to abrasion, erosion, and sliding wear.
Key Properties and Advantage in Coatings
1. Exceptional Hardness (Mohs 9.2-9.5)
Property: Green SiC is one of the hardest synthetic abrasives.
Benefit in Coating: This extreme hardness allows the coating to resist penetration and material removal by abrasive particles (sand, ore, dust). The SiC grains bear the brunt of the mechanical stress, protecting the softer binder matrix (e.g., epoxy, polymer, ceramic).
2. Superior Wear and Abrasion Resistance
Property: High hardness directly translates to excellent resistance against both sliding and impact abrasion.
Benefit in Coating: It is ideal for applications involving the movement of granular materials, such as in mining equipment (slurry pumps, hydrocyclones), material handling systems (hoppers, pipelines), and agricultural machinery.
3. High Thermal Stability and Conductivity
Property: Green SiC is stable at temperatures up to 1600°C and has high thermal conductivity.
Benefit in Coating:
Stability: The coating maintains its integrity in high-temperature environments (e.g., boiler tubes, exhaust systems).
Conductivity: Friction generates heat. The high thermal conductivity of SiC helps dissipate this heat, preventing localized overheating that could soften the binder matrix and lead to premature coating failure.
4. High Chemical Inertness
Property: It offers strong resistance to acids, alkalis, and solvents.
Benefit in Coating: This makes it suitable for corrosive-wear (corrosive-abrasive) environments found in chemical processing, wastewater treatment, and marine applications, where the coating must resist both chemical attack and physical wear simultaneously.
5. Sharp Particle Morphology
Property: Crushed and graded green SiC grains have sharp, angular edges.
Benefit in Coating: These sharp particles anchor themselves more effectively into the binder matrix, improving cohesive strength within the coating and reducing the risk of grain pull-out under stress.