Black Silicon Carbide (Black SiC) Grit 320# & 400# for Brake Pads
Black silicon carbide (Black SiC) 320# and 400# serve as core wear-resistant fillers in brake pads, especially semi-metallic and low-metallic formulations. Their high hardness, thermal stability and consistent friction properties improve braking performance and service life.
I. Core Parameters (JIS Standard)
320#
- SiC content: ≥98.5%
- D50 (median particle size): 40.0±2.5 μm
- Particle size range: D0≤98 μm, D3≤74 μm, D94≥27 μm
- Mohs hardness: 9.15
- Density: 3.2 g/cm³
- Melting point: 2250℃
400#
- SiC content: ≥98.5%
- D50 (median particle size): 30.0±2.0 μm
- Particle size range: D0≤75 μm, D3≤58 μm, D94≥20 μm
- Hardness, density and melting point: same as 320#
II. Functions in Brake Pads
- Wear resistance improvement: As a hard abrasive, it stabilizes the friction coefficient and reduces heat fade.
- High temperature resistance: Performs steadily under braking temperatures of 400–800℃.
- Counterface cleaning: Mildly grinds the brake disc to remove oxide layers and contaminants, preventing noise and judder.
- Matrix reinforcement: Enhances mechanical strength, impact resistance and service life.
III. Selection Differences: 320# vs 400#
320# (Coarser)
- Advantages: Higher friction force, stronger braking performance, better disc cleaning effect, longer service life
- Disadvantages: Slightly higher noise and disc wear, easier to cause judder
- Applications: Heavy-duty vehicles, high-performance cars, semi-metallic formulations
400# (Finer)
- Advantages: Quieter operation, less disc abrasion, better comfort
- Disadvantages: Slightly lower friction force and service life
- Applications: Passenger cars, low-metallic / ceramic formulations, OEM replacement parts
IV. Application Guidelines
- Purity: Select products with SiC≥98.5%, low iron and free carbon content to avoid corrosion and squeal.
- Particle size: Strict D50 control is required; large fluctuations may lead to unstable friction performance.
- Blending: Usually compounded with graphite, zircon, barium sulfate, etc., to balance overall performance.
- Processing: Ensure uniform mixing and stable pressing / sintering to prevent segregation and powder shedding.
V. Common Alternatives & Combinations
- Green silicon carbide: Higher purity and hardness, higher cost, used in high-end ceramic brake pads.
- White fused alumina: Good toughness and impact resistance, applied in heavy-duty formulations.
- 320# + 400# compound: Balances braking strength, quietness and service life.
