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Molybdenum Disulfide Is Used in Brake Pad as an Anti-friction Additive

As a good anti-friction additive, molybdenum disulfide (MoS2) is essential for producing brake pads. The composition of raw materials of brake pads includes four parts: binder, reinforcing fiber, friction performance modifier, and filler. 

There are two type of friction performance modifier. The first one is anti-friction materials. Its addition can improve the friction resistance of the material, reduce noise and friction coefficient. Graphite, molybdenum disulfide, lead, and copper belong to the material. The second one is frictional materials. Its addition can increase the friction coefficient of the material. Most inorganic fillers, some metals and their oxides are included in this category. The friction performance modifier mainly adjusts the thermal stability of the material and its working stability.

MoS2 has advantages of good dispersion, wear resistance and noise reduction, which is widely used in many fields. Its performances in the brake pad as a friction modifier additive as following: 

A. Friction reduction

The regular particle size of MoS2 is 1.1-30 μm with 0.04-0.06 friction coefficient and excellent dispersion to make sure good friction reduction. 

B. Friction enhancement

When the friction temperature of friction material increases sharply, molybdenum disulfide oxidizes to form molybdenum trioxide, which expands with the increase of air temperature and then increases friction.

C. Oxidation resistance and anti shedding

Molybdenum disulfide is slightly acidic. It covers the surface of friction materials to protect other materials from oxidation, so that it is not easy to fall off and has strong adhesion.

D. Expansion

When the friction material is in the high-temperature state of braking, many low-temperature materials such as fillers and resins are easy to be carbonized and burned out, resulting in the increase of internal voids of the materials, while molybdenum trioxide can better make up for it.

E. Reduce the specific gravity

The specific gravity of MoS2 crystal is 4.5-5.2. With the increase of fineness, the specific surface area also increases, and the specific gravity decreases, which reduces the weight of brake pad to a certain extent.

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