An apparatus has: a first member; a shaft rotatable relative to the first member about an axis; and a seal system. The seal system has a seal carrier having: an axially-extending wall having an inner diameter (ID) surface; and a radially-extending wall having a first surface. A seal is carried by the first member and has: an outer diameter (OD) surface; and a seal face. A seat is carried by the shaft and has a seat face in sliding sealing engagement with the seal face. One or more springs bias the seal carrier relative to the first member so as to bias the seal face against the seat face. At least one of the seal carrier inner diameter (ID) surface and seal outer diameter (OD) surface is formed by a coating.