How StopFlex Manufactures Long-Fiber Carbon Ceramic Brakes (C/SiC)

Table of Contents

C/SiC (carbon-fiber reinforced silicon carbide)

A ceramic-matrix composite in which SiC forms the matrix and carbon fibers do the reinforcing. The fiber network carries the load; the matrix keeps the structure stable when it gets hot.

LSI (Liquid Silicon Infiltration)

Molten silicon soaks into a porous carbon structure and reacts in place to form SiC. That reaction is what creates the ceramic matrix and densifies the part.

NVH

Noise, vibration, harshness. On brakes, it usually turns up as squeal, judder, or a “gritty” feel.

Runout

How much the rotor wobbles as it spins. Too much of it brings on pedal pulsation and uneven pad transfer.

Transfer layer

A thin film of pad material left on the rotor that helps steady the friction and the feel.

How to watch this

Treat this clip as context. The steps below walk through what each operation actually controls, and how it shows up in real braking.

• Watch how the preform is handled — that is structure control.
• Watch the finishing stage — geometry and surface control.
• Validation is where a good story has to become a repeatable part.

Step 1 — Carbon fiber weave

We start with continuous carbon fiber and lay up a reinforcement architecture that carries load in several directions at once. This is the skeleton of the rotor.

Out in the real world, braking is a constant heat-up and cool-down, and that cycling is what drives stress into the disc. A continuous network spreads that stress out instead of letting it concentrate in one place.

Step 2 — Preform build

The fiber architecture is brought together with a binder system and a few selected fillers to form a controlled, porous preform. This stage lives or dies on repeatability: placement, chemistry, and porosity.

Porosity is no small thing here. It decides how the silicon will later infiltrate the structure, so when porosity varies, matrix formation varies with it. That can resurface much later as uneven wear, noise, or unstable friction.

Step 3 — Consolidation

The preform is consolidated and shaped close to its final geometry. Doing this now spares us heavy correction machining later, once the part is fully densified and extremely hard.

Near-net shaping is a deliberate choice for keeping variation under control. The less aggressive the late-stage machining, the easier it is to hold geometry that stays consistent from part to part.

Step 4 — Silicon infiltration

Under vacuum or a controlled atmosphere, molten silicon wicks into the porous structure by capillary action. As it goes, it reacts with the carbon to form SiC in place, leaving behind a densified C/SiC composite.

LSI runs hot. Published routes sit above silicon’s melting point of 1,415°C (2,579°F) and are frequently reported in the ~1,500–1,600°C (2,732–2,912°F) range, depending on the recipe and the geometry.

Step 5 — Final machining

Once the part is densified, we finish the ventilation geometry, the faces, and the surface. What we are after here is tight runout, steady pad contact, and predictable airflow.

• Geometry control keeps vibration and uneven pad transfer in check.
• Vent control shapes how the disc cools, which matters most under repeated stops.
• Surface control decides how cleanly the transfer layer forms and settles.

Step 6 — Validation

Each batch is checked for dimensional accuracy and balance, then put on a dynamometer for a long run of repeated high-energy stops. The question we are answering is a practical one: does the friction on the last stop still match the first?

In severe-duty testing, disc surface temperatures can climb into the ~900°C (1,652°F) range. Motorsport manufacturer references also describe carbon-ceramic discs running stably around 600–750°C (1,112–1,382°F), with peaks near 1,000°C (1,832°F), depending on the protocol.