Highly corrosion-resistant porous metal body and method for producing the same

Abstract

Provided are a porous metal body that is excellent in terms of corrosion resistance and that is suitable for a collector for batteries such as lithium-ion batteries, capacitors, or fuel cells; and methods for producing the porous metal body. A production method includes a step of coating a porous nickel body with an alloy containing at least nickel and tungsten or a metal containing at least tin; and a subsequent step of a heat treatment. Another production method includes a step of forming a nickel-plated layer on a porous base and then continuously forming an alloy-plated layer containing at least nickel and tungsten or tin, a step of removing the porous base, and a step of reducing metal. Such a method can provide a porous metal body in which tungsten or tin is diffused in a porous nickel body or a nickel-plated layer.

1 . A method for producing a porous metal body containing at least nickel and tungsten, the method comprising a step of coating a porous nickel body with an alloy containing at least nickel and tungsten; and a step of subsequently performing a heat treatment to diffuse tungsten into the porous nickel body. 
     
     
         2 . The method for producing a porous metal body according to  claim 1 , wherein the porous nickel body is obtained by coating, with nickel, a porous base having been made electrically conductive, removing the porous base, and subsequently reducing nickel. 
     
     
         3 . The method for producing a porous metal body according to  claim 1 , wherein the heat-treated porous metal body has a nickel content of 60 mass % or more and 95 mass % or less and a tungsten content of 5 mass % or more and 40 mass % or less. 
     
     
         4 . The method for producing a porous metal body according to  claim 1 , wherein the heat-treated porous metal body further contains, as a component, 10 mass % or less of phosphorus. 
     
     
         5 . A porous metal body comprising an alloy containing at least nickel and tungsten. 
     
     
         6 . The porous metal body according to  claim 5 , wherein the porous metal body has a nickel content of 60 mass % or more and 95 mass % or less and a tungsten content of 5 mass % or more and 40 mass % or less. 
     
     
         7 . The porous metal body according to  claim 5 , wherein the porous metal body further contains, as a component, 10 mass % or less of phosphorus. 
     
     
         8 . The porous metal body according to  claim 5 , wherein the porous metal body has been subjected to an electrolytic oxidation treatment in liquid so as to have enhanced corrosion resistance. 
     
     
         9 . A method for producing a porous metal body containing an alloy containing at least nickel and tin, the method comprising a step of coating a porous nickel body with a metal containing at least tin; and a step of subsequently performing a heat treatment to diffuse tin into the porous nickel body. 
     
     
         10 . The method for producing a porous metal body according to  claim 9 , wherein the porous nickel body is obtained by coating, with nickel, a porous base having been made electrically conductive, removing the porous base, and subsequently reducing nickel. 
     
     
         11 . A porous metal body comprising an alloy containing at least nickel and tin. 
     
     
         12 . The porous metal body according to  claim 11 , wherein the porous metal body has a tin content of 1 to 58 mass %. 
     
     
         13 . The porous metal body according to  claim 11 , wherein the porous metal body further contains, as a component, 10 mass % or less of phosphorus. 
     
     
         14 . The porous metal body according to  claim 11 , wherein the porous metal body has been subjected to an electrolytic oxidation treatment in liquid so as to have enhanced corrosion resistance. 
     
     
         15 . A method for producing a porous metal body containing at least nickel and tungsten or tin, the method comprising: a step of plating, with nickel, a porous base having been made electrically conductive to form a nickel-plated layer, subsequently washing the nickel-plated layer, and then continuously, without letting a surface of the nickel-plated layer dry, plating the surface of the nickel-plated layer with an alloy containing at least nickel and tungsten or an alloy containing at least nickel and tin to form an alloy-plated layer;
 a step of removing the porous base by heating in an oxidizing atmosphere; and   a step of subsequently reducing metal by performing a heat treatment in a reducing atmosphere,   wherein the step of removing the porous base and the step of reducing metal are performed to diffuse tungsten or tin in the alloy-plated layer into the nickel-plated layer.   
     
     
         16 . The method for producing a porous metal body according to  claim 15 , further comprising, after the step of reducing metal,
 a step of performing a heat treatment in an inert atmosphere or a reducing atmosphere to diffuse tungsten or tin.   
     
     
         17 . The method for producing a porous metal body according to  claim 15 , wherein, after the step of reducing metal, the porous metal body has a nickel content of 60 mass % or more and 95 mass % or less and a tungsten content of 5 mass % or more and 40 mass % or less. 
     
     
         18 . The method for producing a porous metal body according to  claim 15 , wherein, after the step of reducing metal, the porous metal body has a tin content of 1 to 58 mass %. 
     
     
         19 . The method for producing a porous metal body according to  claim 15 , wherein, after the step of reducing metal, the porous metal body further contains, as a component, 10 mass % or less of phosphorus.