Open-porous molded body, method for production and use thereof

Abstract

The invention relates to a method for fabricating an open-porous molded body which is formed from nickel or iron and at least another element which form solid solutions or intermetallic phases as well as a molded body which is correspondingly fabricated, and the use thereof. During the fabrication it is proceeded then, such that a coating with a metallic powder forming solid solutions or intermetallic phases is deposited upon an open-porous body made of nickel or iron by means of an organic binder. Subsequent thereto, the open-porous body provided with the coating is brought into the desired shape with observing minimum bending radii, and subsequently the organic components are removed in a first thermal treatment step. By means of a second thermal treatment the open-porous molded body is sintered, and the solid solution or the intermetallic phase are formed.

1 . A method for fabricating an open-porous molded body which is formed from nickel or iron and at least another metal which form solid solutions or intermetallic phases, or on the surface thereof such solid solutions or intermetallic phases are formed, comprising 
 wherein an open-porous body made of nickel or iron is coated with a metallic powder forming solid solutions or intermetallic phases by means of an organic binder,    subsequently said open-porous body made of nickel or iron is brought into the desired shape with observing minimum bending radii,    then, the organic components are removed in a first thermal treatment step; and    with a second thermal treatment subsequent to said first thermal treatment said open-porous molded body is sintered and said solid solution or said intermetallic phase are formed.    
     
     
         2 . A method according to  claim 1 , characterized in that said organic binder and subsequently said respective metallic powder is deposited upon said surface of said open-porous body made of nickel or iron, and shaping is first performed then.  
     
     
         3 . A method according to  claim 1 , characterized in that pure aluminium powder, aluminium powder containing additional metallic elements or being prealloyed is deposited.  
     
     
         4 . A method according to  claim 1 , characterized in that said body made of nickel or iron coated with said binder or said metallic powder is deformed into a hollow cylinder.  
     
     
         5 . A method according to  claim 4 , characterized in that at least two of such said hollow cylinders are joined to each other with respectively adapted outer and inner diameters.  
     
     
         6 . A method according to  claim 1 , characterized in that said body made of nickel or iron coated with said binder is deformed in a plurality of layers helically around a longitudinal axis in a wrapped shape.  
     
     
         7 . A method according to  claim 6 , characterized in that said deformed coated body made of nickel or iron is enclosed by a cylinder forming an outer circumferential surface.  
     
     
         8 . A method according to  claim 7 , characterized in that said outer circumferential surface of said cylinder is perforated.  
     
     
         9 . A method according to  claim 7 , characterized in that a cylinder made of a metal or a ceramic is used.  
     
     
         10 . A method according to  claim 6 , characterized in that a film also being helically wrapped is wrapped in between helically wrapped layers.  
     
     
         11 . A method according to  claim 10 , characterized in that a perforated film is used.  
     
     
         12 . A method according to  claim 10 , characterized in that a film made of a metal or a ceramic is used.  
     
     
         13 . A method according to  claim 1 , characterized in that said organic binder having low viscosity is deposited upon the surface of said open-porous body by dipping and/or spraying such that the open pore structure is maintained, and merely the ridges of said pores are coated.  
     
     
         14 . A method according to  claim 13 , characterized in that excessive binder is removed by pressing together, blowing through and/or exhausting from said body made of nickel or iron.  
     
     
         15 . A method according to  claim 1 , characterized in that during and/or after the application of said metallic powder said body made of nickel or iron is set into vibration.  
     
     
         16 . A method according to  claim 1 , characterized in that an open-porous body made of nickel or iron is used which has a maximum thickness of 100 mm in a reference plane prior to coating and shaping.  
     
     
         17 . A method according to  claim 1 , characterized in that during the first thermal treatment step a minimum temperature of 250° C. is achieved, and this is maintained over a period of time of at least 15 minutes.  
     
     
         18 . A method according to  claim 1 , characterized in that during the second thermal treatment a minimum temperature of 600° C. is maintained over a period of time of at least 15 minutes.  
     
     
         19 . A method according to  claim 1 , characterized in that in addition at least one further metal in powdery form is added to said respective metallic powder.  
     
     
         20 . An open-porous molded body fabricated with a method according to  claim 1 , characterized in that it is formed from nickel or iron and a metal in the form of a solid solution or as an intermetallic phase, or said surface is formed as such a layer from these said solid solutions and said intermetallic phase, respectively; and said molded body comprises at least curved areas with observing minimum bending radii.  
     
     
         21 . A molded body according to  claim 20 , characterized in that it has been formed from at least one generally plate-like, open-porous body made of nickel or iron obtained by subsequently shaping.  
     
     
         22 . A molded body according to  claim 20 , characterized in that it is formed in shape of a hollow cylinder.  
     
     
         23 . A molded body according to  claim 20 , characterized in that at least two hollow cylinders telescoped into one another are forming said molded body.  
     
     
         24 . A molded body according to  claim 20 , characterized in that it has a helical shape formed around a longitudinal axis.  
     
     
         25 . A molded body according to  claim 20 , characterized in that said porosity varies starting from said inside longitudinal axis radially outwardly step by step or in a graded form.  
     
     
         26 . A molded body according to  claim 20 , characterized in that it is formed from nickel aluminide or iron aluminide, or is coated with it on its surfaces.  
     
     
         27 . A molded body according to  claim 20 , characterized in that a minimum porosity of 85% is achieved.  
     
     
         28 . A molded body according to  claim 20 , characterized in that at least one cylinder forming an outer circumferential surface encloses said open-porous molded body.  
     
     
         29 . A molded body according to  claim 28 , characterized in that said cylinder is perforated.  
     
     
         30 . A molded body according to  claim 28 , characterized in that said cylinder is formed from a metal or a ceramic.  
     
     
         31 . A molded body according to  claim 20 , characterized in that a separating film is arranged is between layers of a helically wrapped, open-porous molded body.  
     
     
         32 . A molded body according to  claim 20 , characterized in that said film is formed from a metal or a ceramic.  
     
     
         33 . A molded body according to  claim 20 , characterized in that said film is perforated.  
     
     
         34 . The use of a molded body according to  claim 20  as a particle filter.