Rotating brake member of braking device for vehicle and method for antirust treatment thereof

摘要

In a cast-iron disc brake rotor (1), each of an outer sliding surface (2a) and an inner sliding surface (3a) is covered with a phosphate coating (8) by electrolysis of a phosphate coating solution containing therein phosphate ions, zinc ions and nitrate ions. This makes it possible to attain dramatically improved rust preventive performance for the sliding surfaces (2a) and (3a). The phosphate coating (8) has a thickness of 1 to 10 mum, a mass of 4 to 35 g/m<2 >and a grain size of less than 50 mum. Preferably, the thickness of the phosphate coating (8) is adjusted to 2 to 8 mum.