Coefficient of Friction The coefficient of friction of a
composite material is not a constant. It is dictated by the
materials of the mating contact surfaces and by the roughness of
the harder one. With combinations that have very different
strength values (such as polymer with steel), the coefficient of
friction also depends on the load. In addition, due to the
polymer's strong tendency to change all mechanical properties
under temperature, the coefficient of friction is also affected
by speed and ambient temperature. The coefficient of friction
drops as load increases and as speed decreases. It also changes
as the bearings wear. During the wear-in period, NORGLIDE®
bearings are shortly exposed to higher wear. A polymer transfer
layer forms on the metal contact surface. After wear-in, a
relatively constant performance range is found, which is
controlled by the pure PTFE compound layer. With bronze
reinforced NORGLIDE® bearing types, the coefficient of friction
increases slightly after prolonged service due t