The invention relates to gas turbine engine seal systems having a rotating member with an abrasive tip surface disposed in rub relationship to a stationary seal member with an abradable surface. The abrasive tip surface is coated with a metallic alloy matrix having ceramic abrasive particles embedded in and projecting from the matrix. The abradable seal surface is coated with a ceramic coating. The rub relationship affords a tight operating clearance between the rotating member and the stationary seal member, thereby improving engine efficiency, reducing fuel consumption and minimizing overhaul downtime.