Method For Producing A Metal Foam And Method For Producing Particles Suitable For Said Method

Abstract

A method for producing a metal foam includes depositing metal-containing particles and blowing-agent-containing particles by cold spraying. A layer formed in this manner is formed from metallic particles and particles containing blowing agent, wherein the blowing agent forms the core of coated particles. The shell of said particles is likewise metallic, such that it is easier to deposit said particles together with the metallic particles. Therefore, a higher concentration of blowing agent can advantageously be produced in the layer. Greater possibilities are advantageously produced thereby to provide the porous layers with required pore profiles.

What is claimed is: 
     
         1 . A method for producing a metal foam, comprising:
 depositing (a) exclusively metal-containing particles together with (b) coated particles having a core consisting of a solid blowing agent and a metallic shell as a layer on a substrate by cold spraying, and   activating the blowing agent, which forms pores of the metal foam in the layer.   
     
     
         2 . The method of  claim 1 , wherein the metallic shell includes aluminum, copper, nickel, iron, steel or silver. 
     
     
         3 . The method of  claim 1 , wherein the metallic shell is formed from the same material as the exclusively metal-containing particles. 
     
     
         4 . The method of  claim 1 , wherein the core includes magnesium hydride, titanium hydride, calcium carbonate, or magnesium carbonate. 
     
     
         5 . The method of  claim 1 , comprising varying a mixing ratio between the coated particles containing the solid blowing agent and the exclusively metal-containing particles during the depositing step. 
     
     
         6 . The method of  claim 5 , wherein the method is performed such that the layer is formed with variable density of the pores. 
     
     
         7 . The method of  claim 6 , wherein the density of the pores in at least one of a boundary layer adjacent the substrate or a boundary layer near an outer surface of the layer is reduced to zero by processing only the exclusively metal-containing particles at the respective boundary layer. 
     
     
         8 . The method of  claim 5 , wherein a density of the pores in a boundary layer adjacent the substrate is maximized by processing only the particles containing the blowing agent. 
     
     
         9 . The method of  claim 1 , comprising activating the blowing agent to form the metal foam by performing a heat treatment of the layer after completion of the depositing step. 
     
     
         10 . The method of  claim 1 , comprising adding energy during the depositing step or adding energy to the substrate such that upon impacting the substrate during the depositing step, the particles containing the blowing agent are heated to a temperature above a reaction temperature of the blowing agent. 
     
     
         11 - 12 . (canceled)