High porosity metal biporous foam

Abstract

An environmentally friendly process for producing metal biporous foam by using filamentary metal powders such as nickel or copper. The filamentary metal powders are initially wet when combined with a suitable foam former such as methylcellulose. Because the filamentary metal powder is wet, it does not extract water from the foam structure thereby ensuring a highly porous metal foam having both high macroporosity and microporosity.

1 . A process for producing metal biporous foam comprising; 
 a) providing metal powder, b) wetting and mixing the metal powder with a liquid to form a wet metal containing solution mixture,    c) creating a foam from a foam precursor,    d) combining the foam and the wet metal containing solution mixture together and mixing same,    e) drying the foam to form a green cake, and    f) sintering the green cake to form a metal biporous foam.    
   
   
       2 . The process according to  claim 1  wherein the metal powder is filamentary powder.  
   
   
       3 . The process according to  claim 1  wherein the metal powder is selected from at least one of the group consisting of nickel, copper, iron, nickel-base alloys, copper-base alloys, and iron-base alloys.  
   
   
       4 . The process according to  claim 1  including forming the foam from at least one of the group consisting of methylcellulose and hydroxylpropyl methylcellulose.  
   
   
       5 . The process according to  claim 1  including mixing the metal powder with a surfactant to form the wet metal containing solution mixture.  
   
   
       6 . The process according to  claim 1  including adding water to the metal powder to form the wet metal containing solution mixture.  
   
   
       7 . The process according to  claim 1  including creating the foam by adding water to the foam former to form a foam precursor and allowing the foam precursor to thicken.  
   
   
       8 . The process according to  claim 7  wherein glycerin is added to the foam precursor.  
   
   
       9 . The process according to  claim 1  including forming the foam to a density of about 0.5 g/cc.  
   
   
       10 . The process according to  claim 1  wherein the metal biporous foam has a porosity of about 85%-95%.  
   
   
       11 . The process according to  claim 1  wherein the metal biporous foam has a density of about 5%-15% metal.  
   
   
       12 . The process according to  claim 2  wherein the filamentary powder is derived from a metal carbonyl source.  
   
   
       13 . The process according to  claim 1  wherein a foaming agent selected from at least one of the group consisting of air, carbon dioxide and nitrous dioxide creates the foam.  
   
   
       14 . The process according to  claim 1  wherein mechanical means create the foam.  
   
   
       15 . The process according to  claim 1  wherein the foam is heated to above its thermal gelation temperature.  
   
   
       16 . A process for producing metal biporous foam comprising: 
 a) providing metal powder,    b) wetting and mixing the metal powder with a liquid to form a wet metal mixture,    c) providing a foam,    d) combining the foam and the wet metal mixture,    e) drying the combined foam and wet metal mixture to form a green cake, and    f) sintering the green cake to form a metal biporous foam.    
   
   
       17 . The process according to  claim 16  wherein the metal powder is filamentary powder.  
   
   
       18 . The process according to  claim 16  wherein the metal biporous foam has a porosity of about 85%-95%.  
   
   
       19 . The process according to  claim 16  wherein the metal biporous foam has a density of about 5%-15% metal.  
   
   
       20 . The process according to  claim 16  wherein the metal powder is derived from a carbonyl source.  
   
   
       21 . The process according to  claim 16  wherein the combined foam and wet metal mixture is heated to above its thermal gelation temperature.