Wollastonite comes in two forms: acicular wollastonite fiber and wollastonite powder. Acicular wollastonite fiber is resistant to chemical corrosion from acids and alkalis. Its aspect ratio ranges from 18:1 to 20:1, providing a reinforcing effect that increases with the aspect ratio. Wollastonite powder, a calcium metasilicate mineral, offers good friction-enhancing properties. In asbestos-free products, wollastonite fiber achieves a reinforcing effect equivalent to that of Grade 6 asbestos. By combining wollastonite fiber with a small amount of high-strength fibers, friction material products with sufficient performance can be manufactured. As a result, it has been widely adopted by numerous friction material manufacturers and companies.