Production of boric acid added brake friction composite and the effect of heat treatment on braking characterization

Abstract

Purpose The purpose of this study was to investigate the use of boric acid as a friction modifier material in brake friction composites and to determine the effect of heat treatment applied during production on braking performance. Design/methodology/approach The addition of five different amounts of boric acid was balanced with cashew, which is in the friction modifier material group. The samples were produced in the following order: dry mixing, preforming and hot-pressing. The effect of the heat treatment that can be applied after the hot-pressing process on the braking performance was investigated. The tribological and physical properties of the samples were determined using tests performed according to appropriate standards. The microstructures of the friction surfaces were investigated using scanning electron microscopy. Findings It was observed that the tribological properties of brake friction composites containing 20% by weight of boric acid were improved. It has also been observed that the heat treatment applied after hot pressing increased the friction coefficient of the samples by 7% on average and decreased the specific wear ratio of the samples. When the surface morphologies of the samples are examined, it is seen that the friction layers of the heat-treated samples are wider, and the microvoids and cracks are reduced. Originality/value This study showed that boric acid can be used as a friction modifier in brake friction composites. It also revealed the tribological and physical contribution of the applied heat treatment to the composite. Thus, it guides brake friction composite manufacturers in the industry and researchers working in this field.