In all metal - metal combinations adhesion occurs. Typical adhesion effects are recognized
by material transfer and an irregular groove pattern.
The coefficient of friction
is maximal for materials with high shear strength! A friction load of half
normal load may occur in dry rubbing metal - metal combinations.
For Teflon it is known that a low friction and a high wear rate can be expected.
The wear rate of Aluminum or Brass or Teflon against steel is unacceptable large
In the combination steel - steel or bronze - steel the wear rate is certainly
not bad however, the coefficient of friction will be unacceptable.