The brake pads are generally composed of a bottom plate, an adhesive insulation layer and a friction layer, wherein the heat insulation layer is composed of a poor heat conductive material and a reinforcing material. The friction layer consists of a reinforcing material, a binder and a filler (friction modifier). For the brake pads, the most important thing is the choice of friction material, which basically determines the braking performance of the brake pads. Friction materials are distinguished from basic materials including asbestos, semi-metallic and organic (NAO). China in 1999 to prohibit the use of asbestos in the friction plate, the current domestic general use of semi-metallic friction materials, the use of steel or copper materials. The basic quality requirements of brake pads are: wear resistance, friction coefficient, excellent insulation performance.