Copper sulfide in friction materials not only increases the friction coefficient and provides certain anti-friction properties at low temperatures, but also effectively dissipates heat at high temperatures due to its high thermal conductivity.
Under the general trend of copper-free formulations, the use of copper sulfide in overall formulations can fully meet the requirement of a content below 5%.

Blackish-brown amorphous powder or granular substance. Soluble in dilute nitric acid, hot concentrated hydrochloric acid, sulfuric acid, and sodium cyanide solution; slightly soluble in ammonium sulfide solution; insoluble in water and sodium sulfide solution. It can be oxidized into a colloidal state in humid air.