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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.

Copper and copper alloys are widely used in friction materials such as brake pad formulations as one of key ingredients by providing good thermal conductivity and high temperature friction stability to achieve desired friction performance, fade and wear resistance. However, the use of copper or copper containing material is being restricted in brake pads due to environment and health concerns. Extensive works have been made to explore the copper substitutes but most of these efforts became ineffective and failed with issues either thermal fade or excessive pad/rotor wear. In this paper, friction and wear responses were examined when a metallic composite material was used as the copper substitute in NAO and Low-met brake formulations where the copper and copper alloys were added 8% and 22% respectively.

The brake wear contribution to the environmental pollution has been extensively discussed, with major focus on asbestos and heavy metals released to the environment. Only limited attention was paid to released organic compounds generated during friction processes, although the organic and carbonaceous components are not the minor part in brake lining formulations. Friction processes in brakes are associated with relatively high temperatures and high pressures on the friction surfaces which relates to the thermal decomposition of the organic components in friction materials and to brake lining thermal fade. Thus, this study focuses on the identification of organic compounds released from a model low metallic brake material.