The Influence of Biocarbon Powder Produced from a Pine Nutshell on Tribotechnical Properties of Copper Based Friction Material Running Under Conditions of Boundary Friction

This article describes the analysis of influence of biocarbon (BC) produced by pyrolysis from a pine nutshell on tribological properties of friction material. The research object has been presented by copper-based friction material doped with 12% tin with 10–40 vol % of carbon additive in the form of BC. The average particle size of BC is 10 μm. The tribological properties has been analyzed using an IM-58 friction machine. The tribological tests demonstrate that with an increase in the BC content the dynamic friction coefficient increases from 0.041 to 0.066. With the aim of comparison, addition of GE-1 grade powdered graphite results in an increase in the friction coefficient from 0.038 to 0.069. Simultaneously with the increase in friction coefficient the wear of friction material also increases not exceeding its ultimate value. Thus, at 10 vol % of BC addition the wear is 4.0 μm/km, at 40 vol %, 12.1 μm/km. Analysis of surface morphology of bronze demonstrates that the BC particles are worn uniformly with bronze layer, retaining the initial porous structure. The products of BC destruction with sizes of 50–500 nm have been introduced into the surface layer of bronze. The results demonstrate opportunities of biocarbon additive in friction material, which can be used as a substitution of conventionally used graphite. It should be mentioned that the promising opportunities of BC addition to powdered antifriction material are determined by initial raw material for its production.