# US 11,299,814 B2 · Method for treating a surface of a metallic structure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,299,814 B2 - Document ID: US11299814B2 - Status: Granted - Kind: B2 - Application number: 16/668,147 - Filed: 2019-10-30 - Published: 2021-05-06 - Granted: 2022-04-12 - Earliest claimed: 2019-10-30 - Assignees: City University of Hong Kong - Applicants: City University of Hong Kong - Inventors: Jian Lu; Yang Yang Li; Weihui Ou; Binbin Zhou; Junda Shen; Chenghao Zhao - Web page: https://patentgrep.com/patent/US11299814B2 ## CPC - C25D 11/024: {Anodisation under pulsed or modulated current or potential} - C25D 5/18: Electroplating using modulated, pulsed or reversing current - C25D 5/34: Pretreatment of metallic surfaces to be electroplated - C25D 5/605: {Surface topography of the layers, e.g. rough, dendritic or nodular layers} - C25F 3/02: Etching - C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR - C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR ## Abstract A method for treating a surface of a metallic structure, the metallic structure being made of a first metallic material, the method including the steps of: (a) releasing metallic ions from the surface of the metallic structure; and (b) depositing a nano-structured metallic layer onto the surface of the metallic structure from the released metallic ions, wherein the nano-structured metallic layer includes uniform nanoparticles. ## Claims ### Claim 1 A method for treating a surface of a metallic structure, the method comprising the steps of: (a) releasing metallic ions from the surface of the metallic structure, the metallic structure comprising a first metallic material selected from the group consisting essentially of silver metal, a silver alloy, and a combination thereof; and (b) depositing the released metallic ions onto the surface of the metallic structure to form a nano-structured metallic layer, wherein the nano-structured metallic layer includes uniform nanoparticles, wherein the size of the nanoparticles is in a range between 100 to 600 nm; wherein the method is performed using an electrochemical cell comprising a first electrode, a second electrode, and an electrolyte in electrical connection with the first electrode and the second electrode, wherein the metallic structure to be treated is connected as the first electrode, and wherein prior to step (a) the electrolyte does not contain the metallic ions to be deposited. ### Claim 2 (depends on 1) The method of claim 1, wherein the surface of the metallic structure is subjected to alternating electrochemical oxidation and reduction through a pulsed voltage or current waveform. ### Claim 3 (depends on 2) The method of claim 2, wherein metallic atoms of the metallic structure are oxidized to metallic ions thereby releasing from the surface of the metallic structure during oxidation. ### Claim 4 (depends on 2) The method of claim 2, wherein the metallic ions are reduced to metallic atoms thereby forming the nano-structured metallic layer on the surface of the metallic structure during reduction. ### Claim 5 (depends on 1) The method of claim 1, wherein the releasing of the metallic ions in step a) is carried out by applying a first voltage for a first duration to the metallic structure; and the deposition of the released metallic ions in step b) is carried out by applying a second voltage different from the first voltage for a second duration to the metallic structure obtained after step (a). ### Claim 6 (depends on 5) The method of claim 5, wherein the size of the nanoparticles is manipulated by the first and second voltages and the first and second durations. ### Claim 7 (depends on 5) The method of claim 5, wherein the first duration and the second duration are each ranged from 0.001 s to 7200 s. ### Claim 8 (depends on 5) The method of claim 5, wherein the first voltage is a positive or zero voltage, and the second voltage is a negative voltage. ### Claim 9 (depends on 1) The method of claim 1 wherein the silver alloy further includes a second metallic material and the second metallic material is selected from Cu, Co, Fe, or Ni. ### Claim 10 (depends on 1) The method of claim 1 wherein the electrolyte includes an acid. ### Claim 11 (depends on 10) The method of claim 10, wherein the acid includes at least one of nitric acid and citric acid. ### Claim 12 (depends on 1) The method of claim 1, wherein the electrolyte further includes an additive for manipulating the size of the nanoparticles. ### Claim 13 (depends on 12) The method of claim 12, wherein the additive includes at least one of acid, water soluble polymer, sodium citrate, polystyrene sulfonate, sodium dodecyl sulfate (SDS), and cysteine. ### Claim 14 (depends on 13) The method of claim 13, wherein the water soluble polymer includes polyvinylpyrrolidone (PVP) or polystyrene sulfonate. ### Claim 15 (depends on 1) The method of claim 1, wherein the nanoparticles of the nano-structured metallic layer form one or more metal nanostructures. ### Claim 16 (depends on 15) The method of claim 15, wherein the morphologies of metal nanostructures include at least one of nanospheres, nanospindles, nanoplates, nanopyramids, nanowires, nanocones, nanoshuttles, and dendrites. ### Claim 17 (depends on 1) The method of claim 1 wherein the electrolyte, upon completion of step (b), includes morphologies of nanoparticles of the first metallic material. ### Claim 18 (depends on 17) The method of claim 17, wherein the morphologies of nanoparticles include at least one of nanocones, nanopyramids, nanorods, nanowires, and nanostars. ### Claim 19 (depends on 1) The method of claim 1, further including step d) of separating metallic nanoparticles from the electrolyte by centrifugation. ### Claim 20 (depends on 1) The method of claim 1, further including step c) of repeating steps a) and b). ### Claim 21 (depends on 20) The method of claim 20, wherein steps a) and b) are repeated for 10-15000 cycles. ### Claim 22 (depends on 1) The method of claim 1, further including step a0), prior to step a), of washing the metallic structure via sonication sequentially in acetone, ethanol, and water, each for a predetermined period. ### Claim 23 (depends on 22) The method of claim 22, further including step a1), following step a0), of drying the metallic structure under steam of nitrogen. ### Claim 24 (depends on 2) The method of claim 2, wherein the voltage or current waveform is square-shaped, triangular-shaped, or sinusoidal-shaped. ### Claim 25 (depends on 1) The method of claim 1, wherein the metallic structure is in the form of a wire, a foil, a mesh, a foam, a porous structure or a needle. ### Claim 26 (depends on 1) The method of claim 1, wherein the metallic structure is a substrate for Surface Enhanced Raman Spectroscopy (SERS), sensing, catalysis, therapeutics or plasmoelectronics.