Zircon powder, a mineral – based powder with unique properties, has become an important additive in the production of brake shoes. As brake shoes are key components for vehicle safety, the quality of brake shoes friction materials within brake shoes mixtures or brake shoes mixes is of utmost importance. Zircon powder contributes significantly to enhancing the performance of these friction materials.

Zircon powder serves several crucial functions in brake shoes friction materials. First and foremost, it acts as a high – temperature stabilizer. In a typical brake shoes mixture, adding 5 – 8% zircon powder by weight can effectively improve the high – temperature resistance of the friction material. When the friction surface temperature reaches 400°C, the structure of the friction material with zircon powder remains relatively stable, while without it, the material may start to decompose or lose its mechanical integrity.

Secondly, zircon powder can enhance the hardness of the brake shoes friction materials. In a laboratory – made brake shoes mix, the addition of 6 – 10% zircon powder can increase the hardness of the friction material by about 15 – 20% on the Rockwell hardness scale. This increase in hardness helps the brake shoes to better withstand the abrasive forces during braking.

Zircon powder endows brake shoes with outstanding heat – resistance properties. During extreme braking conditions, such as continuous high – speed braking, the temperature on the friction surface of brake shoes can rise rapidly. Brake shoes with zircon powder in their friction materials can maintain a stable coefficient of friction even when the temperature reaches up to 500°C. Tests show that the coefficient of friction only fluctuates within a range of ±0.05, while in brake shoes without zircon powder, the coefficient of friction may drop by 0.1 – 0.2 under the same high – temperature conditions.

Brake shoes containing zircon powder exhibit excellent wear – resistance characteristics. Wear tests conducted under standard braking cycles demonstrate that the wear rate of friction materials with zircon powder is 30 – 40% lower than that of those without it. This significantly extends the service life of the brake shoes, reducing the frequency of replacement and maintenance costs for vehicle owners.

Zircon powder contributes to the chemical stability of the brake shoes friction materials. It can resist chemical reactions with various substances in the braking environment, such as moisture and acidic gases. In a humid and slightly acidic environment, the friction material with zircon powder shows no signs of significant degradation even after exposure for 1000 hours, while the material without zircon powder may experience a 20 – 30% reduction in its mechanical properties.

Zircon powder, especially the high – purity grade required for brake – shoe production, is relatively expensive. The cost of zircon powder is approximately 3 – 5 times higher than some common fillers used in brake shoes mixtures. This high cost can substantially increase the production cost of brake shoes, posing a challenge for manufacturers aiming to produce cost – effective products.

Zircon powder has relatively high hardness and melting point, which makes it difficult to process in the production of brake shoes friction materials. Special processing techniques and equipment are often required to evenly disperse zircon powder in the mixture. For example, high – energy ball – milling is usually needed to reduce the particle size of zircon powder to a suitable range for uniform mixing, which adds to the production complexity and cost.

In conclusion, zircon powder offers remarkable advantages in improving the performance of brake shoes, but its high cost and processing difficulties need to be carefully considered and addressed in the brake – shoe production process.