The use of wollastonite in friction products is relatively common, particularly in industries where high-performance friction materials are required. Wollastonite offers several beneficial properties that make it suitable for use in friction products:
High Hardness
Wollastonite has a Mohs hardness ranging from 4.5 to 5.5, making it a suitable abrasive material for enhancing the frictional properties of brake pads, clutch linings, and other friction components.
Low Abrasiveness
Despite its hardness, wollastonite exhibits relatively low abrasiveness, which helps to reduce wear on mating surfaces and extend the lifespan of friction materials.
Heat Resistance
Wollastonite has excellent heat resistance, with a melting point exceeding 1,400°C. This property is crucial in friction applications where materials are subjected to high temperatures generated during braking or clutch engagement, ensuring stable performance under extreme conditions.
Chemical Inertness
Wollastonite is chemically inert, which means it does not react with other materials commonly found in friction formulations. This stability contributes to consistent friction performance and prevents degradation of friction materials over time.
Reinforcement
The fibrous morphology of wollastonite particles provides reinforcement to the friction matrix, enhancing the structural integrity and mechanical properties of the friction material.
Reduction of Noise and Vibration
Wollastonite’s fibrous structure can help dampen noise and reduce vibration in friction systems, resulting in quieter and smoother operation.
Due to these advantageous properties, wollastonite is used in various friction products, including automotive brake pads, clutch linings, industrial brake linings, and friction tiles for machinery and equipment.
While wollastonite may not be as commonly used as other fillers such as graphite, carbon fibres, or ceramic fibres in friction materials, its unique combination of properties makes it a valuable additive in certain applications where specific performance requirements need to be met.