Influence of SiC, SiO2 and graphite on corrosive wear of bronze composites subjected to acid rain

Sintered aluminum bronze friction materials have been successfully used in clutches and breaks for heavy-duty applications, due to their good wear resistance, cold workability, fatigue resistance and corrosion resistance. The aim of the present work is the preparation and investigation of bronze-based composites for components subjected to motion in aqueous environments. Three of bronze-based composites with different amounts of slide additive (graphite) and friction additives (SiC, SiO₂) were prepared by powder metallurgy. The microstructure profiles of the obtained composite materials were characterized by uniform distribution of SiC, SiO₂ and graphite particles within the bronze matrix. The porosity decreased with increase in the number of pressing and sintering processes. High Vickers hardness values were registered for samples with higher reinforcement contents.A combination of electrochemical and gravimetric techniques was used in this study to assess corrosive wear rates of these materials under neutralized as well as acid rain conditions. Increasing both slide and friction additives improved the corrosion resistance of these bronze composites. Samples with 1.5% graphite, 3% SiO₂ and 3% SiC had the highest corrosive wear resistance in neutralized as well as in acid rain due to the high amount of anti-friction and slide additives, in addition to low porosity.