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Automotive brake linings are complex composite materials. Some raw materials used by manufacturers or the compounds created during the friction process might be potentially hazardous and may cause various adverse effects. Different fractions of the brake wear debris can be released during braking: i) the airborne and ii) the nonairborne. Due to the small size and minimum gravitational action, the airborne particles could be spread for long distances from a source and typically remain suspended in the air for long periods of time. Our previous research demonstrated that the airborne fraction contains considerable amounts of different nanoparticulates. On the other hand, the emitted nonairborne fraction typically settles on vehicle/brake hardware surfaces and in the vicinity of roads. The nonairborne particles are considered to be relatively large, but it was shown that nano-sized particles readily attach to them and can be released later.

The major goal of this research study was to address the possible replacement of copper and selected solid lubricants by environmentally friendly hexagonal boron nitride (h-BN). Model friction samples were manufactured and subjected to friction assessment and screening tests (FAST) and full scale automotive brake dynamometer (Dyno) tests. The SAE recommended J2430 procedure provided the necessary data for the Brake Effectiveness Evaluation Procedure (BEEP) by Brake Manufacturers' Council. The obtained results indicate that the overall coefficient of friction, as detected in FAST, increased with respect to baseline with a 1:1 substitution of h-BN for either Cu or metal sulfides (Sb₂ S₃ and MoS₂). The thickness losses in FAST tests were similar or lower when h-BN was being used to replace copper and metal sulfides, except for the HCR type of h-BN.

The purpose of this research study was to develop Cu-free automotive brake materials. Model brake material samples were manufactured and subjected to full scale automotive brake dynamometer (Dyno) tests using SAE J2430 test procedure. The SAE recommended J2430 test procedure provided the necessary data for the Brake Effectiveness Evaluation Procedure (BEEP) by the Brake Manufacturers' Council. The Dyno results indicate that the friction level of the all four Cu-free samples was similar to the baseline material. All tested brakes have passed the Brake Effectiveness Evaluation Procedure (BEEP). The average effectiveness of Baseline (BL), GT1, GT2, T401 and T402 samples is 0.32, 0.31, 0.30, 0.31 and 0.31, respectively. The Dyno results show that the Cu-free samples had similar or better performance compared to the baseline material as the temperature of the brake increased in the fade section. However, the Cu-free samples exhibit slightly higher wear rate in Dyno tests.

Brake linings have complex microstructure and consist of different components. Fast growing automotive industry requires new brake lining materials to be developed at considerably shorter time periods. The purpose of this research was to generate the knowledge for optimizing of brake friction materials formula with mathematical methods which can result in minimizing the number of experiments/test, saving development time and costs with optimal friction performance of brakes. A combination of processing methods, raw materials and testing supported with the Artificial Neural Network (ANN) and Taguchi design of experiment (DOE) allowed achieving excellent results in a very short time period. Friction performance and wear data from a series of Friction Assessment and Screening Test (FAST) were used to train an artificial neural network, which was used to optimize the formulations. The averaged COF, COF variation and wear were used as the output parameters.