Wollastonite, a calcium inosilicate mineral, has found significant application in the production of brake shoes. Brake shoes are crucial components in vehicle braking systems, and the quality of the friction materials used in them directly impacts braking performance and safety.

In brake shoes mixes, wollastonite serves multiple important functions. Firstly, it acts as a reinforcement agent. When incorporated into the brake shoes friction materials, it can enhance the mechanical strength of the mixture. For example, in a typical brake shoes mixture, adding 10 – 15% wollastonite by weight can increase the flexural strength of the friction material by about 15 – 20%. This improvement in strength is vital as it ensures that the brake shoes can withstand the high mechanical stresses generated during braking without breaking or deforming easily.

Secondly, wollastonite is beneficial for heat dissipation. During braking, a large amount of heat is generated due to friction. Wollastonite – containing brake shoes friction materials have better heat – dissipation properties. Tests show that brake shoes with wollastonite can reduce the maximum temperature on the friction surface by 20 – 30°C compared to those without it, when subjected to the same braking conditions, which helps to prevent the fade of braking performance caused by overheating.

Wollastonite contributes to stable friction performance. In standard braking tests, brake shoes with wollastonite in their friction materials maintain a relatively stable coefficient of friction. The coefficient of friction can be maintained within a range of 0.35 – 0.45 under different braking speeds (from 30 km/h to 120 km/h), which is crucial for ensuring consistent braking force and vehicle controllability.

Brake shoes with wollastonite exhibit excellent wear resistance. Laboratory wear tests indicate that the wear rate of friction materials with wollastonite can be reduced by 30 – 40% compared to traditional friction materials without wollastonite. This not only extends the service life of the brake shoes but also reduces the frequency of replacement, saving costs for vehicle owners.

One of the main drawbacks is the cost. Wollastonite, especially high – purity wollastonite suitable for brake – shoe production, is relatively expensive. The cost of wollastonite can be 2 – 3 times higher than some common filler materials in the brake – shoe industry. This higher cost may increase the overall production cost of brake shoes, which could be a concern for manufacturers aiming to produce low – cost products.

There can be compatibility issues in some brake shoes mixes. In certain formulations, wollastonite may not blend well with other components in the brake shoes friction materials. This can lead to problems such as uneven distribution of the mineral in the mixture, which in turn may affect the overall performance of the brake shoes, causing local variations in friction and wear.

In conclusion, while wollastonite offers significant advantages in terms of friction stability and wear resistance in brake shoes production, its high cost and potential compatibility issues need to be carefully considered and addressed during the manufacturing process.