... ,300mesh,400mesh D50 20-30um pure lead powderlead powderPb powderlead metal powderPb metal powderspherical lead powdermetal lead powderatomized lead powderpure Pb powder ... self-lubricated, structural parts of powder metallurgy, friction discs, sheathing boards of brakes, clutches, metal-graphite electric brushes, diamond grinding wheels, bronze ...