Composite brake pads
With the emergence of the transmission system, the brake pads also came into being. It can be said that where there is a transmission, there is a friction system as a guarantee.
Are the brake pads composite? It is undeniable, because the formula often contains fibers and performance regulators, and then the resin is used as a binder, and it is formed after hot pressing, which is a very typical composite material.
So how to design the brake pads?
Starting from the material of brake pads, it can be divided into asbestos and non-asbestos. However, since asbestos is a strong carcinogen, from the mid-1970s to the mid-1980s, all countries began to use non-asbestos formulas.
At present, the asbestos-free formula is mainly divided into three types: semi-metal, less metal and metal-free (NAO). For a brake pad, what users require is good wear resistance, high temperature zone performance after frictional heat generation, and now more and more attention to noise issues. As people pay more and more attention to the noise problem, a large number of enterprises and research institutions are now vigorously developing NAO formulations, hoping that the performance in the high temperature zone will also maintain the original level.
The metal-less (NAO) formula dissipates heat quickly and has a high friction coefficient, but it is noisy and causes great damage to the disk; the metal-free formula has a lot of organic components, but it is easy to carbonize in high-temperature areas, and its performance decreases accordingly. In the formula we personally designed this time, the resin uses phenolic resin, which has better high temperature resistance. Other ingredients and their corresponding effects are as follows:
Reinforcing fiber: carbon fiber, aramid fiber (organic 6%<10%), steel fiber (inorganic), composite fiber (6% is noisy, should not be too high)
Grinding agent: friction particles, zirconia (oxide, more expensive, but less noisy than alumina), magnesia, potassium hexatitanate whisker
Lubricant: copper sulfide, artificial graphite (to reduce damage to the disc)
Other regulators: nitrile powder, 2-8 brass powder, barium sulfate, calcium carbonate (adjust pH)
In the actual production process, engineers will change the proportion and type of raw materials in the formula according to the customer's requirements for friction coefficient and noise, etc., and then make a small sample for testing, then make improvements, test, and finally produce and sell.
