Method of making a PTFE based tape suitable for impregnation into a porous metal matrix

摘要

A method of making a tape suitable for impregnation into a porous metal matrix which generally includes 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. In addition, some of the PTFE based composition may be left above the porous metal interlayer after the impregnation step. After sintering, a composite bearing material which may include a metal backing, a porous metal interlayer on the metal backing, and having the PTFE based composition substantially filling the pores of the porous metal interlayer and forming a surface layer on the bearing material may thereby be produced.