Thin porous layer with open porosity and a method for production thereof

Abstract

The aim of the invention is to produce a thin porous layer, with a defined porosity and also, a high strength. Said aim is achieved, whereby such a layer with open porosity is produced from a mixture, comprising a sinterable powder with a predetermined powder particle size distribution. The sintered layer is of a thickness, which corresponds to about triple the average diameter of the powder particles employed, has a pore diameter in the range from 0.01 to 50 μm and a tensile strength of in a range from about 5 to 500 N/mm 2 . The invention further relates to a method for the production of said thin porous layer with open porosity.

What is claimed is:  
     
         1 . Thin porous layer with open porosity, manufactured from a mixture containing sinterable powder with a predetermined powder particle size distribution, whereby the sintered layer has a thickness which is at least triple the average diameter of the used powder particles, a defined pore diameter in a range of about 0.01 to 50 μm and a tensile strength in a range of about 5 to 500 N/mm 2 .  
     
     
         2 . Thin porous layer in accordance with  claim 1 , marked by a maximum thickness of about 500 μm.  
     
     
         3 . Thin porous layer in accordance with one of the above claims marked by self-supporting properties.  
     
     
         4 . Thin porous layer in accordance with one of the above claims marked by a bubble-point pressure in a range of about 8×10 6  to 2×10 3  Pa.  
     
     
         5 . Thin porous layer in accordance with one of the above claims marked by the content of inorganic and/or organic pore forming material in the mixture.  
     
     
         6 . Thin porous layer in accordance with one of the above claims marked by a graded design.  
     
     
         7 . Procedure for manufacturing thin porous layer with open porosity in accordance with one of the  claims 1  to  6 , whereby the layer is made up of a mixture containing sinterable powder and the sinterable powder with a predetermined size distribution of powder particles is suspended along with particles of the defined size as pore forming material is suspended in a carrier fluid. It is applied in at least one layer on a carrier body, dried and the green layer thus formed is sintered.  
     
     
         8 . Procedure in accordance with  claim 7  marked by the correspondence of the portion of pore forming materials in the suspension to the metallic layer to be produced in about the defined pore volume.  
     
     
         9 . Procedure in accordance with  claim 7  or  8  marked by the forming of the carrier fluid by the binding agent liquefied with a solvent.  
     
     
         10 . Procedure in accordance with one of the  claims 7  to  9  marked by the suspension of pore forming materials of different densities and/or sizes in the solvent for obtaining a graded layer design.  
     
     
         11 . Procedure in accordance with one of the  claims 7  to  10  marked by the application of the suspension in many partial layers one after another on the carrier body.  
     
     
         12 . Procedure in accordance with one of the  claims 7  to  11  marked by drying of the earlier partial layer before the application of the next partial layer.  
     
     
         13 . Procedure in accordance with one of the  claims 7  to  12  marked by the sintering of the earlier partial layer before application of the next partial layer.  
     
     
         14 . Procedure in accordance with one of the  claims 7  to  13  marked by the application of the suspension on the carrier body by the process of thin layer pouring, spraying or immersing.  
     
     
         15 . Procedure according to one of the  claims 7  to  14  marked by the application of the suspension on at least on one of the walls of a porous, preferably pipe-shaped carrier body made from sinterable material, dried and the green layer thus formed subsequently firmly sintered on the carrier body.  
     
     
         16 . Procedure in accordance with one of the  claims 7  to  15  marked by the rotation of the pipe-shaped carrier body around the axis of the pipe during application of suspension and at least during some part of the drying period.  
     
     
         17 . Using a thin porous layer with open porosity in accordance with one of the  claims 1  to  6  as filter material, catalyst, membrane reactor, friction substance, filter cartridge and/or filter pipe.