RIZHAO DSS AUTO SPARE PARTS CO., LTD.

Brake pads are more than just friction material—their performance depends heavily on chemical composition and environmental factors. Two critical but often overlooked elements are halogens and moisture. Let’s explore how they influence braking efficiency, safety, and longevity.

1. The Role of Halogens in Brake Pads
What Are Halogens?
Halogens, such as chlorine (Cl) and bromine (Br), are chemical elements sometimes used in brake pad formulations. They serve specific functions:

• Heat Resistance – Help maintain stability at high temperatures.
• Friction Modifiers – Adjust brake pad grip under different conditions.
• Flame Retardants – Bromine compounds can reduce flammability.

Potential Problems with Halogens
Despite their benefits, halogens can cause issues:

• Corrosion – When heated, halogens may release hydrochloric acid (HCl) or hydrogen bromide (HBr), which corrode brake rotors and calipers.
• Environmental & Health Risks – Some halogenated compounds are restricted under REACH (EU) and RoHS due to toxicity concerns.
• Performance Degradation – Over time, halogen-induced corrosion can reduce braking consistency.

Halogen-Free Brake Pads: A Growing Trend
Many modern brake pads now avoid halogens, using alternatives like:

• Ceramic compounds (silica, alumina)
• Mineral fibers (basalt, wollastonite)
• Non-halogenated resins (phenolic, polyimide)

These materials reduce corrosion risks while maintaining performance.

2. Moisture’s Impact on Brake Pads
How Moisture Gets into Brake Pads
Water can enter brake pads through:

• Manufacturing – If raw materials (resins, fibers) absorb humidity.
• Storage – Improperly sealed pads may soak up moisture from the air.
• Usage – Driving in rain or washing the car can temporarily wet the pads.

Why Moisture is a Problem

• Initial Braking Fade – Wet pads may have reduced friction until the water evaporates (called “water fade”).
• Structural Damage – Moisture can weaken resin binders, leading to cracks.
• Rust Formation – Prolonged exposure accelerates corrosion on brake rotors.

How Manufacturers Minimize Moisture Issues
To ensure reliability, high-quality brake pads undergo:

• Thermal Curing – Heating at 120–150°C to remove trapped moisture.
• Hydrophobic Materials – Using carbon or ceramic fibers that repel water.
• Sealed Packaging – Vacuum-sealed bags with desiccants prevent moisture absorption before installation.

3. Key Takeaways for Brake Pad Longevity

• Halogens can improve heat resistance but may cause corrosion over time.
• Moisture reduces initial braking efficiency and may damage pad structure.
• Halogen-free & moisture-resistant formulations are becoming industry standards.

Understanding these factors helps in selecting better brake pads for safety and durability.