Embedding and compacting particles in porous surfaces

DETAILED DESCRIPTION The invention claimed is: 1.
In the process for preparing a metallic surface having pores in which particles are embedded therein which comprises: a.
heating a porous metallic surface to at least 100.
degree.
F and not more than 650.
degree.
F to enlarge the pores thereof, said pores initially having an average width not greater than 100 microns; b.
promptly thereafter depositing finely divided particles having an average size no greater than 50 microns onto said heated surface and working said particles into said pores, said particles being at a temperature at least 100.
degree.
F below the temperature of said heated surface and being selected from the class consisting of perfluorocarbon polymers, elemental metals, metal oxides, metal nitrides, metal carbides and metal disulfides; and c.
permitting said surface and particles to reach room temperature thereby to lock said particles into said pores; the improvement comprising: d.
subjecting a surface produced according to steps (a), (b) and (c) to a fluid stream having finely divided solid particles suspended therein at a pressure of 30-120 psi for a sufficient period to compact the embedded particles, said suspended particles having an average size no greater than 50 microns; e.
thereafter heating said surface to a temperature of at least 100.
degree.
F.
f.
promptly thereafter depositing additional finely divided particles similar to those already embedded in said pores onto said heated surface and working said particles into said pores, said particles being at a temperature at least 100.
degree.
F below the temperature of said heated surface; and g.
permitting said surface and particles to reach temperature equilibrium, thereby to lock said additional particles into said pores.
2.
The process of claim 1 in which both the deposited and the suspended compacting particles are perfluorocarbon polymer particles.
3.
The process of claim 1 in which both the deposited and the suspended compacting particles are polytetrafluoroethylene particles