Abstract: The present invention relates to a method of impregnating into a porous metal matrix mounted on a backing a PTFE based composition wherein the PTFE based composition is mounted on a layer of supporting material so as to form a tape to assist in carrying it to and forcing it into the porous metal matrix, whereupon the layer of supporting material is removed. In one embodiment, the present invention may be in the form of a composite bearing material having a metal backing supporting a PTFE filled porous metal matrix of bronze or other copper alloys and a surface layer above the porous metal matrix of just the PTFE based composition.

Abstract: The present invention relates to a composite bearing material comprising three layers: (1) a metal backing, (2) a porous metal interlayer bonded to the metal backing which includes bronze or other copper alloy particles from two distinct particle size ranges and (3) a PTFE based composition intermixed with and overlying the porous metal interlayer. In accordance with the method of the present invention, the porous metal interlayer substantially comprises a relatively non-homogeneous mixture of particles from the two distinct particle size ranges, wherein a substantial portion of the relatively fine powder is segregated adjacent the metal backing. The present invention includes a significant thickness of the PTFE based composition applied to and remaining above the surface of the porous metal backing.

Abstract: The present invention relates to a method of making a tape suitable for impregnation into a porous metal matrix which generally comprises the steps of mixing a liquid dispersion of PTFE with a coagulant to form a paste, placing the paste between a layer of supporting material and a layer of filter paper to form a sandwich, compressing the sandwich, transferring the sandwich to a gauze-like material so that the filter paper layer of the sandwich is adjacent the gauze-like material, applying a vacuum to the gauze-like material and adjacent filter paper layer to remove some excess liquid from the paste, and removing the layer of filter paper from the sandwich to leave a tape comprising PTFE and liquid and a layer of supporting material adjacent the tape. The method of the present invention may be used to apply, by impregnation, a PTFE based composition, which may include various fillers therein, to a porous metal matrix or interlayer.