Why Must Brake Pads Be Both Wear-resistant And Corrosion-resistant?

As a core friction component in a vehicle's braking system, brake pads' performance directly determines the vehicle's braking efficiency and safety factor. During daily driving, brake pads are constantly subjected to high-frequency friction, high temperatures, and complex environmental corrosion, making wear resistance and corrosion resistance essential core attributes. This article will delve into why brake padsmust balance wear resistance and corrosion resistance, focusing on braking principles, usage scenarios, and the synergy between related components.

I. Wear Resistance: The Fundamental Guarantee for Sustained and Stable Braking Performance

The wear resistance of brake pads is directly related to their service life and the stability of braking force. It is a core capability for handling high-frequency friction and heavy loads.

1. The Inevitability and Dangers of Friction Loss

The essence of the braking process is the conversion of kinetic energy into heat through intense friction between the brake pad and the brake disc (or brake drum). During this process, the friction material on the brake pad surface inevitably wears away due to compression and sliding:

• Ordinary family cars: During urban commuting, brake pads experience dozens or even hundreds of braking cycles daily, with friction pressures reaching 5-10 MPa per braking event. Annual wear typically ranges from 1-3 mm.

• Commercial vehicles: When a heavy-duty truck's brake pads are fully loaded and traveling downhill, friction pressures can soar to over 20 MPa. Combined with high temperatures (above 600°C), wear can reach as much as 0.5 mm on a single, long downhill trip.

  Inadequate brake pad wear resistance can lead to:

• Braking force loss: Excessive wear can cause the brake pad thickness to decrease dramatically, reducing the contact area with the brake disc, reducing braking force, and increasing stopping distance (experimental data shows that reducing brake pad thickness from 10 mm to 3 mm can increase stopping distance by 15%-20%).

• Frequent replacement hazards: Low-quality brake pads can completely wear out within 10,000-20,000 kilometers. Failure to replace them promptly can cause the metal backing plate to rub directly against the brake disc, leading to abnormal brake squeal, disc scratches, and even brake failure.

2. Technical Path to Wear Resistance

To improve wear resistance, the friction material of brake pads must be precisely formulated:

• Metal-based brake pads: By adding hard components such as cast iron fibers and copper powder (comprising 30%-50%), the high hardness of the metal resists friction loss. Suitable for heavy-duty applications such as commercial vehicles, they offer a service life of over 100,000 kilometers.

• Ceramic-based brake pads: Using ceramic and aramid fibers as their backbone and wear-resistant fillers (such as alumina), they maintain a stable coefficient of friction while reducing wear by 40% compared to conventional organic brake pads, making them a popular choice for passenger cars.

• Structural Reinforcement: Some high-performance brake pads utilize a gradient layer design. A surface layer of highly wear-resistant material mitigates initial friction, while an inner layer of cushioning material reduces impact, extending overall service life.

II. Corrosion Resistance: A Performance Preservative in Complex Environments

Brake pads operate in environments far from a closed, ideal environment. Instead, they are exposed to corrosive substances such as water, salt, and dust for extended periods. Therefore, corrosion resistance is crucial for maintaining their stable performance.

1. Sources of Corrosion and Damage Mechanisms

Brake pad corrosion primarily arises from three sources:

• Environmental Attack: When driving in the rain, rainwater seeps into the gap between the brake pad and the brake disc. If the vehicle is parked for extended periods, this water reacts with the metal components in the friction material to oxidize, forming a rust layer (also known as "brake galling"), which can cause abnormal brake squeal or momentary braking force fluctuations during cold starts.

• Road Salt: Calcium chloride and sodium chloride in winter de-icing agents adhere to the brake pad surface, destroying the structural integrity of the friction material through electrochemical corrosion, causing the surface layer to powder and flake. (In cold northern regions, salt corrosion can shorten brake pad life by 20%-30%). • Brake fluid leakage contamination: If the brake lines are not properly sealed, brake fluid (including components such as ethylene glycol) can leak onto the brake pad surface, dissolving the organic binders in the friction material, resulting in a decrease in material strength and a sharp drop in the coefficient of friction.

2. Application and Practice of Anti-Corrosion Technology

To combat corrosion, brake pads employ multiple protective measures in terms of materials and processes:

• Surface Coating: The backing plate (metal portion) of the brake pad is sprayed with a zinc-based coating or electrophoretic paint, which can withstand salt spray tests for over 500 hours, effectively isolating it from moisture and salt.

• Waterproof Friction Formula: The addition of a hydrophobic agent (such as a silane coupling agent) reduces moisture adhesion to the friction material surface, reducing the likelihood of rust.

• Sealed Edge Design: A rubber edge seal wraps around the side of the brake pad to prevent dust and liquid from penetrating the friction material, making it particularly suitable for muddy and dusty off-road driving.

III. The Consequences of Ignoring Wear and Corrosion Resistance: From Failure to Safety Accidents

Countless cases have proven that deficient brake pad wear and corrosion resistance are the main causes of brake failure:

• Case 1: A logistics truck used low-quality brake pads (with insufficient wear resistance). During a long downhill descent in a mountainous area, the brake pads completely wore out within three hours. Direct friction between the metal backing plate and the brake drum caused the drum to overheat and glow red, ultimately leading to brake failure and a rear-end collision.

• Case 2: A car was parked in a coastal area for an extended period. The brake pads rusted and adhered due to poor corrosion resistance. Upon restarting the car, the brakes seized, causing the vehicle to veer off the road and crash into a guardrail.

• Statistics: According to spot checks by the General Administration of Quality Supervision, Inspection and Quarantine, 70% of substandard brake pads in 2024 failed to meet wear resistance standards, and 30% experienced premature performance degradation due to corrosion failure.

A brake pad's wear resistance and corrosion resistance essentially provide a dual guarantee for sustained braking performance and environmental adaptability. Wear resistance ensures the pad survives high-frequency, high-load friction, while corrosion resistance ensures stable performance under the erosion of water, salt, and dust. These two functions are not isolated; rather, they work in conjunction with components such as the brake disc and clutch plate to form a safety barrier for the braking system.

For consumers, choosing brake pads that have passed authoritative certifications such as ECE R90 and FMVSS 135 (all of which include rigorous wear and corrosion testing), regularly checking brake pad thickness (recommended every 20,000 kilometers), and selecting specialized corrosion-resistant models based on the operating environment (such as coastal areas or cold regions) are key to ensuring driving safety. Remember, brake pad performancenot only affects vehicle wear but also directly determines the reliability of each braking action—this is the ultimate significance of wear and corrosion resistance.If you are looking for high-performance and durable brake pads,you can visit our website:https://www.evfriction.com.Please contact us by  +86-13363216781 or jessicabrakes12@gmail.com if you have any questions.