In my last post I talked a bit about how and why disc brakes are good braking solutions for many vehicles. We discussed how they work, where they’re positioned in a vehicle and a few other details. In this post I’d like to talk about the actual disc brake pad materials – what they are and why they’re so good at slowing vehicles down. The brake pad is, basically, what it sounds like. It’s a pad that is involved in the brake assembly, and it assists with braking. How does it do this? Brake pads are composed of friction materials. When they are forced into contact with the spinning brake disk, the friction caused by the interaction between the disc and the pad causes the rotation of the axel to which the disc is attach to slow, which in turn slows the automobile.

Brake pads are composed of materials that are intended to maximize the friction between the pad and the disc. In the past, brake pads were composed of asbestos, which was highly valued as a friction material. However, when it became clear to health care professionals that asbestos was poisonous to humans, it was phased out as a brake pad material. Mechanics were exposed to asbestos dust while installing and servicing asbestos brake pads, so in order to reduce the risks to humans, asbestos was replaced with other materials. Today, brake pads are composed of a range of materials, depending on the application. Modern brake pads are often composed of ceramic materials, semi-metallic materials, aramid fibers, plastics like Kevlar and even glass and cellulose. Each material offers its own set of benefits and drawbacks, such as noise generation, heat generation, brake disc wear inducement, environmental friendliness and stopping capability. Choosing the right disc brake pad material depends on the application, and engineers are usually in the best position to make such a decision.