Manufacturing Process & Material Data Sheet

1. Detailed Manufacturing Process — C/C-SiC Technology

1.1 Fiber Type and Structural Design

Fiber Type:
High-strength or high-modulus PAN-based carbon fiber, typically equivalent to T700 grade carbon fiber.

Fiber Architecture:
A quasi-three-dimensional 2.5D fiber structure, typically manufactured using needling or weaving techniques, is adopted to provide multidirectional fiber reinforcement and structural stability.

1.2 Preform Manufacturing

Preform manufacturing is a critical process for ensuring dimensional accuracy, uniform fiber distribution, and structural integrity of the final component.

Fiber Weaving:
Long carbon fibers are woven into a brake-disc-shaped preform using a three-dimensional weaving process. A 5-directional weaving architecture is employed to achieve uniform fiber distribution throughout the preform.

Impregnation:
The woven preform is impregnated with a phenolic resin binder using a vacuum impregnation process.

• Vacuum level: ≤ 50 Pa

• Impregnation time: 30 min

This process ensures sufficient penetration of the resin into the spaces between the carbon fibers.

Curing and Carbonization:
The impregnated preform is placed in a high-temperature processing furnace and subjected to a controlled multi-stage heating cycle:

• Heat from room temperature to 90°C within 15 min, then hold for 60 min

• Increase temperature to 120°C and hold for 15 min

• Applied pressure: 0.5–1 MPa

• Increase temperature to 150°C and hold for 10 min to complete curing

After curing, the preform undergoes carbonization to remove volatile components from the resin system and form a low-density C/C composite carbon skeleton.

The fiber volume fraction of the resulting preform is approximately 40%.

Preform Reinforcement:
Needling technology is used to introduce vertically oriented carbon-fiber bundles, creating a reinforced preform with continuous fiber reinforcement through the thickness direction.

1.3 CVI — Chemical Vapor Infiltration

CVI is a key densification process in which gaseous carbon precursors penetrate the pores of the carbon-fiber preform and deposit carbon within the internal structure.

Typical CVI Parameters

Precursor Gas:

• Methane (CH₄)

• Propylene (C₃H₆)

• Natural gas

• Hydrogen (H₂)

Deposition Temperature:
900–1100°C

Deposition Pressure:
Low-pressure environment, typically from several kilopascals up to atmospheric pressure, depending on the process design.

Densification Effect

During the CVI process, the low-density carbon-fiber preform, typically around 0.4–0.6 g/cm³, is gradually densified into a porous C/C composite.

The material density can reach approximately 1.3 g/cm³, while 15–25% interconnected open porosity remains within the material.

These interconnected pores provide the necessary pathways for subsequent liquid silicon infiltration.

1.4 LSI — Liquid Silicon Infiltration

LSI is the critical process used to convert the porous C/C composite into a C/C-SiC ceramic matrix composite.

Step 1 — Pre-treatment

The CVI-treated C/C preform is placed in a vacuum degreasing furnace to remove residual surface contaminants and volatile substances.

This treatment helps maintain open infiltration channels and improves the efficiency of subsequent silicon infiltration.

Step 2 — Vacuum Silicon Infiltration

The pre-treated C/C preform is placed inside a graphite crucible together with high-purity industrial silicon.

• Silicon purity: ≥99.9%

• Vacuum pressure: ≤50 Pa

• Infiltration temperature: approximately 1700°C

• Holding time: 30 min

The silicon is heated until fully molten and infiltrates the interconnected pores of the C/C preform under vacuum conditions.

Step 3 — Reaction and Cooling

Molten silicon penetrates the porous C/C structure through capillary forces.

The silicon reacts with the carbon matrix and selected carbon surfaces to form silicon carbide according to the following reaction:

Si + C → SiC

The reaction forms a SiC ceramic matrix within the carbon-fiber-reinforced structure, significantly improving the material's high-temperature performance, wear resistance, and thermal stability.

After the infiltration process, controlled cooling is performed at approximately 50°C/h to reduce thermal gradients and minimize the risk of cracking.

Step 4 — Finishing and Machining

After cooling, residual free silicon on the surface is removed. The brake disc is then precision-machined to the required dimensional specifications.

The typical final density of the C/C-SiC composite is approximately:

2.0–2.2 g/cm³

2. Material Certificate / Technical Data Sheet

Technical Summary

ZORVANT C/C-SiC carbon-ceramic brake discs are manufactured through a multi-stage fiber preform, carbonization, CVI densification, and liquid silicon infiltration process. The resulting composite combines a multidirectional long-carbon-fiber reinforcement structure with a SiC ceramic matrix, providing low density, high-temperature resistance, wear resistance, corrosion resistance, stable friction performance, and excellent thermal-shock resistance.