Hierarchical porous metals with deterministic 3d morphology and shape via de-alloying of 3d printed alloys

Abstract

The present disclosure relates to a system for using a feedstock to form a three dimensional, hierarchical, porous metal structure with deterministically controlled 3D multiscale porous architectures. The system may have a reservoir for holding the feedstock, the feedstock including a rheologically tuned alloy ink. A printing stage may be used for receiving the feedstock. A processor may be incorporated which has a memory, and which is configured to help carry out an additive manufacturing printing process to produce a three dimensional (3D) structure using the feedstock in a layer-by-layer fashion, on the printing stage. A nozzle may be included for applying the feedstock therethrough onto the printing stage. A de-alloying subsystem may be used for further processing the 3D structure through a de-alloying operation to form a de-alloyed 3D structure having several distinct, differing pore length scales ranging from a digitally controlled macroporous architecture to a nanoporosity introduced by the de-alloying operation.

1 . A system for using a feedstock to form a three dimensional, hierarchical, porous metal structure with deterministically controlled 3D multiscale porous architectures, the system comprising:
 an reservoir for holding the feedstock, the feedstock being formed as a rheologically tuned alloy ink;   a printing stage for receiving the feedstock;   a processor including a memory and configured to help carry out an additive manufacturing printing process to produce a three dimensional (3D) structure using the feedstock in a layer-by-layer fashion, on the printing stage;   a nozzle for applying the feedstock therethrough onto the printing stage;   a de-alloying subsystem for further processing the 3D structure through a de-alloying operation to form a de-alloyed 3D structure having several distinct, differing pore length scales ranging from a digitally controlled macroporous architecture to a nanoporosity introduced by the dealloying operation.   
     
     
         2 . The system of  claim 1 , wherein the feedstock comprises an alloy powder. 
     
     
         3 . The system of  claim 1 , wherein the rheologically tuned alloy ink comprises an ink formed from a plurality of different metal powders and a binder. 
     
     
         4 . The system of  claim 1 , wherein the additive manufacturing printing process comprises a direct ink writing (DIW) process. 
     
     
         5 . The system of  claim 1 , wherein the additive manufacturing printing process comprises at least one of:
 a direct ink writing (DIW) process;   a selective laser sintering process;   a selective laser melting process;   a binder powder bed printing process;   a fused deposition modeling process;   a projection microstereolithography process;   an electrophoretic deposition process;   a screen printing process; and   an inkjet printing process.   
     
     
         6 . The system of  claim 3 , wherein the rheologically tuned alloy ink comprises an ink formed from silver powder and gold powder. 
     
     
         7 . The system of  claim 6 , wherein the rheologically tuned alloy ink comprises also comprises an organic binder. 
     
     
         8 . The system of  claim 1 , further comprising an annealing subsystem for performing an annealing operation on the 3D structure prior to performing the de-alloying operation. 
     
     
         9 . The system of  claim 8 , wherein the annealing subsystem is configured to heat the 3D structure to 0.99%-0.7% of a melting temperature of an alloy being used to form the 3D structure. 
     
     
         10 . The system of  claim 9 , wherein the annealing subsystem is configured to maintain the 3D structure heated for between 1 hour to 24 hours. 
     
     
         11 . The system of  claim 1 , wherein the de-alloying subsystem enables submerging the 3D structure in an aqueous solution for a predetermined time. 
     
     
         12 . A system for forming a three dimensional, hierarchical, porous metal structure with deterministically controlled 3D multiscale hierarchical pore architectures, the system comprising:
 a printing stage;   an additive manufacturing system including a processor having a nozzle, and configured to print a three dimensional (3D) structure in a layer-by-layer process by flowing a rheologically tuned ink through the nozzle onto the printing stage and to build up the 3D structure in a layer-by-layer;   an annealing subsystem configured to anneal the 3D structure to remove the binder, and to form an alloyed 3D structure; and   a de-alloying subsystem configured to de-alloy the alloyed 3D structure to form a hierarchical, nanoporous 3D structure having an engineered, digitally controlled macropore morphology with integrated nanoporosity.   
     
     
         13 . The system of  claim 12 , wherein the rheologically tuned ink comprises an ink from a plurality of metal powders and a binder. 
     
     
         14 . The system of  claim 12 , wherein the annealing subsystem is configured to heat the 3D structure to 99%-0.7% of the melting temperature of an alloy to be formed as the alloyed 3D structure. 
     
     
         15 . The system of  claim 14 , wherein the annealing subsystem is further configured to heat the 3D structure for a predetermined time period from between 1 hour to 24 hours. 
     
     
         16 . The system of  12 , wherein the de-alloying subsystem is configured to enabling submerging the alloyed 3D structure in a solution. 
     
     
         17 . A system for forming a three dimensional, hierarchical, porous metal structure with deterministically controlled 3D multiscale hierarchical pore architectures, the system comprising:
 a printing stage;   a rheologically tuned, flowable ink including a metal powder and a binder;   an additive manufacturing system including a processor for controlling a printing process, and also having a nozzle, and configured to print a three dimensional (3D) structure in a layer-by-layer process by flowing the rheologically tuned ink through the nozzle onto the printing stage, to build up the 3D structure in a layer-by-layer printing operation;   an annealing subsystem configured to anneal the 3D structure by heating the 3D structure for a predetermined time period to remove the binder, to form an alloyed 3D structure; and   a de-alloying subsystem configured to de-alloy the alloyed 3D structure to form a hierarchical, nanoporous 3D structure having an engineered, digitally controlled macropore morphology with integrated nanoporosity.   
     
     
         18 . The system of  claim 17 , wherein the metal powder of the rheologically tuned ink comprises a mixture of a plurality of different metal powders and the binder. 
     
     
         19 . The system of  claim 17 , wherein the annealing subsystem is configured to heat the 3D structure to 99%-0.7% of the melting temperature of an alloy to be formed as the alloyed 3D structure, for a predetermined period of time. 
     
     
         20 . The system of  claim 19 , wherein the de-alloying subsystem is configured to enabling submerging the alloyed 3D structure in an aqueous solution for a predetermined period of time.