Etched filler containing polytetrafluoroethylene bearing material

Claim 1

METHOD OF FORMING AN ARTICLE SUITABLE FOR USE IN CONSTRUCTION OF BEARING EXHIBITING A LOW COEFFICIENT OF FRICTION IN CONJUNCTION WITH GOOD WEARING PROPERTIES AND LOAD-BEARING CHARACTERISTICS, COMPRISING THE STEPS OF (A) UNIFORMLY INCORPORATING INTO POLYTETRAFLUOROETHYLENE A FINE PARTICULATE INORGANIC FILLER IN AN AMOUNT EQUIVALENT TO BETWEEN ABOUT 10 AND 50% BY VOLUME OF THE MIXTURE THUS FORMED; (B) SHAPING SAID MIXTURE INTO AN ARTICLE OF A DESIRED CONFIGURATION THEREBY FORMING A MATRIX OF SAID POLYTETRAFLUOROETHYLENE CONTAINING SAID FILLER; AND (A) TREATING THE SURFACE OF SAID ARTICLE WITH A SUBSTANCE DESTRUCTIVELY REACTIVE WITH SAID FILLER AND INERT TOWARD SAID POLYTETRAFLUOROETHYLENE UNDER THE CONDITIONS OF TREATMENT AT A TEMPERATURE AND FOR A TIME SUFFICIENT TO FORM PITS NO DEEPER THAN THE SMALLEST DIMENSION OF SAID FILLER IN SAID SURFACE, SAID PITS HAVING RIDGES OF SAID POLYFLUOROETHYLENE NO GREATER THAN A FEW MOLECULES HIGH.