The effect of phenolic resin, potassium titanate, and CNSL on the tribological properties of brake friction materials

Tribological properties of phenolic resin, potassium titanate whiskers, and cashew nut shell liquid (CNSL) cured by aldehide were investigated using a pad-on-disk type friction tester. They were typical ingredients used in the commercial brake pads and, in this study, their friction properties were evaluated using a non-asbestos organic type formulation. Results showed that the phenolic resin increased the coefficient of friction while it revealed high noise propensity during sliding. On the other hand, the noise occurrence was reduced by increasing the CNSL in the friction material. Wear resistance of the friction material was enhanced by additional phenolic resin, whereas potassium titanate and CNSL deteriorated wear resistance. This investigation also suggested that the brake pads having low hardness, high porosity, and high compressibility tended to reduce noise propensity.