It is a sulphide with special properties given that Sb (III) can be oxidized to Sb (V) and is considered a friction stabiliser to protect the brake disc from oxidation due to friction. Tribochemical oxidation is much faster that thermal oxidation, therefore its reduction and containment are fundamental in metallic parts. It is considered as a coadjuvant to graphite molybdenum disulphide by favouring their lubricating effect and, mainly.