Process for the electrolytic polishing of a metallic substrate

Patent metadata

Field	Value
Publication number	US-11162185-B2
Application number	US-201715842652-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 21, 2016
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

The present disclosure is directed a process for the electrolytic polishing of a metallic substrate, including the steps of (i) providing an electrolyte in an electrolytic cell having at least one electrode, (ii) disposing a metallic substrate as an anode in the electrolytic cell, (iii) applying a current at a voltage of 270 to 315 V from a power source between the at least one electrode and the metallic substrate, and (iv) immersing the metallic substrate in the electrolyte, wherein the electrolyte includes at least one acid compound, at least one fluoride compound, and at least one complexing agent.

First claim

What is claimed is:

1. A process for the electrolytic polishing of a metallic substrate, comprising the steps of:
providing an electrolyte in an electrolytic cell comprising at least one electrode;
disposing a metallic substrate as an anode in the electrolytic cell;
applying a current at a voltage of 270 to 315 volts from a power source between the at least one electrode and the metallic substrate; and
immersing the metallic substrate in the electrolyte;
wherein the electrolyte comprises at least one acid compound, at least one fluoride compound, and at least one complexing agent.

2. The process according to claim 1 , wherein the current is applied at a voltage of 285 to 305 volts.

3. The process according to claim 1 , wherein the electrolyte has a temperature in the range of 10 to 95° C.

4. The process according to claim 1 , wherein the current is applied at a current density in the range of 0.05 to 10 A/cm 2 .

5. The process according to claim 1 , wherein the current is applied for a time in the range of 1 to 240 min.

6. The process according to claim 1 , wherein the metallic substrate includes Ti-6A1-4V.

7. The process according to claim 1 , wherein the metallic substrate includes Inconel 718, wherein Inconel 718 is a metal alloy consisting of from 50 to 55 wt. % nickel plus cobalt, from 17 to 21 wt. % chromium, from 4.75 to 5.5 wt. % niobium plus tantalum, from 2.8 to 3.3 wt. % molybdenum, from 0.65 to 1.15 wt. % titanium, from 0.2 to 0.8 wt. % aluminum, no more than 1 wt. % cobalt, no more than 0.8 wt. % carbon, no more than 0.35 wt. % manganese, no more than 0.35 wt. % silicon, no more than 0.015 wt. % phosphorous, no more than 0.015 wt. % sulfur, no more than 0.006 wt. % boron, and no more than 0.3 wt. % copper, with the balance being iron and unavoidable impurities.

8. The process according to claim 1 , wherein the metallic substrate includes Invar, wherein Invar is an alloy of iron and nickel.

9. The process according to claim 1 , wherein the at least one acid compound is in an amount of from 1 to 5 wt.-%, the at least one fluoride compound is in an amount of from 4 to 10 wt.-%, and the at least one complexing agent is in an amount of from 1 to 3 wt.-%, based on the weight of the electrolyte.

10. The process according to claim 1 , wherein the at least one acid compound is in an amount of from 1 to 10 wt.-%, the at least one fluoride compound is in an amount of from 2 to 15 wt.-%, and the at least one complexing agent is in an amount of from 0.5 to 5 wt.-%, based on the weight of the electrolyte.

11. The process according to claim 1 , wherein the at least one acid compound is sulfuric acid.

12. The process according to claim 1 , wherein the at least one fluoride compound is ammonium fluoride.

13. The process according to claim 1 , wherein the at least one complexing agent is methylglycinediacetic acid (MGDA).

14. The process according to claim 1 , wherein the current is applied at a voltage of 298 to 302 volts.

15. The process according to claim 1 , wherein the electrolyte has a temperature in the range of 75 to 85° C.

16. The process according to claim 1 , wherein the current is applied at a current density in the range of 0.1 to 1.5 A/cm 2 .

17. The process according to claim 1 , wherein the electrolyte further comprises at least one medium selected from the group consisting of C 1 to C 8 aliphatic alcohols, C 1 to C 8 aliphatic ethers, C 1 to C 8 aliphatic esters, C 1 to C 8 aliphatic carboxylic acids, and mixtures thereof.

18. The process according to claim 1 , wherein the electrolyte further comprises at least one medium selected from the group consisting of water, alcohols, ethers, esters, carboxylic acids, and mixtures thereof, wherein the electrolyte further includes additives selected from surfactants, polyvalent alcohols, silicates and thickeners, wherein the at least one medium is in an amount of from 70 to 85 wt.-% and the additives are in an amount of from 0.01 to 2 wt.-%, based on the weight of the electrolyte.

19. The process according to claim 1 , wherein the at least one acid compound is sulfuric acid, wherein the at least one fluoride compound is ammonium fluoride, and wherein the at least one complexing agent is methylglycinediacetic acid (MGDA).

20. The process according to claim 1 , wherein:
the at least one acid compound is selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, formic acid, acetic acid, propionic acid, or mixtures thereof;
the at least one fluoride compound can serve as a source of fluoride ions;
the at least one complexing agent is selected from the group consisting of methylglycinediacetic acid (MGDA), ethylenediaminetetraacetate (EDTA), diethylenetriaminepentakismethylenephosphonic acid (DTPMP), aminopolycarboxylic acids (APC), diethylenetriaminepentaacetate (DTPA), nitrilotriacetate (NTA), triphosphate, 1,4,7,10 tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), phosphonate, gluconic acid, β alaninediactetic acid (ADA), N-bis[2-(1,2 dicarboxy-ethoxy)ethyl]glycine (BCA5), N-bis[2-(1,2-dicarboxyethoxy)ethyl]aspatic acid (BCA6), tetracis(2-hydroxypropyl)ethylenediamine (THPED), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) or mixtures thereof; and
the at least one acid compound is in an amount of not more than 20 wt.-%, the at least one fluoride compound is in an amount of not more than 40 wt.-%, and the at least one complexing agent is in an amount of not more than 30 wt.-%, based on the weight of the electrolyte.

Assignees

• Airbus Defence & Space Gmbh

Inventors

• Bagehorn Sarah
• Mertens Tobias

Classifications

• C25F3/16 Primary

  Polishing · CPC title

• C25F3/24

  of iron or steel · CPC title

• C25F3/18 Primary

  of light metals · CPC title

• C25F7/00

  Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects (for both electrolytic coating and removal C25D); Servicing or operating · CPC title

• C25F3/26 Primary

  of refractory metals · CPC title