Electrolyte for electrochemical machining of γ-γ″ nickel-based superalloys

Patent metadata

Field	Value
Publication number	US-11712744-B2
Application number	US-201917290945-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Dec 17, 2018
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

An electrolyte for the electrochemical machining of a γ-γ″ nickel-based superalloy, includes NaNO3 in a content of between 10% and 30% by weight relative to the total weight of the electrolyte; a complexing agent selected from sulfosalicylic acid at a pH of between 3 and 10 and nitrilotriacetic acid at a pH of between 7 and 14, the complexing agent being present in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, an anionic surfactant in a content of between 1% and 5% by weight relative to the total weight of the electrolyte; optionally, NaOH in order to obtain the desired pH; and an aqueous solvent.

First claim

The invention claimed is:

1. An electrolyte for electrochemical machining of a γ-γ″ nickel-based superalloy, comprising:
NaNO 3 in a content of between 10% and 30% by weight relative to the total weight of the electrolyte;
a complexing agent selected from sulfosalicylic acid at a pH of between 3 and 10 and nitrilotriacetic acid at a pH of between 10 and 14, the complexing agent being present in a content of between 1% and 5% by weight relative to the total weight of the electrolyte;
optionally, an anionic surfactant in a content of between 1% and 5% by weight relative to the total weight of the electrolyte;
optionally, NaOH in order to obtain the desired pH;
an aqueous solvent.

2. The electrolyte as claimed in claim 1 , comprising the anionic surfactant.

3. The electrolyte as claimed in claim 2 , wherein the anionic surfactant is selected from the group consisting of saccharin, sodium dodecylsulphate, sulfonates, carboxylates, sulfocinates, phosphates, and mixtures thereof.

4. The electrolyte as claimed in claim 2 , wherein the anionic surfactant is selected from the group consisting of saccharin, sodium dodecylsulphate and mixtures thereof.

5. The electrolyte as claimed in claim 1 , wherein the complexing agent is sulfosalicylic acid at a pH of between 3 and 10.

6. A process for the electrochemical machining of a γ-γ″ nickel-based superalloy, comprising the following successive steps:
a—providing a γ-γ″ nickel-based superalloy workpiece as an anode;
b—providing a tool as a cathode;
c—providing the electrolyte as claimed in claim 1 ;
d—immersing the anode and the cathode in the electrolyte with an inter-electrode distance of between 0.1 and 1 mm;
e—applying a continuous current between the anode and the cathode so as to achieve the anodic dissolution of the γ-γ″ nickel-based superalloy workpiece;
f—recovering the machined workpiece obtained in step e).

7. A process for precision electrochemical machining of a γ-γ″ nickel-based superalloy, comprising the following successive steps:
A—providing a γ-γ″ nickel-based superalloy workpiece as an anode;
B—providing a tool as a cathode;
C—providing the electrolyte as claimed in claim 1 ;
D—immersing the anode and the cathode in the electrolyte;
E—applying a pulsed current between the anode and the cathode, synchronized with a possible oscillation of the cathode, and accompanied by a possible rectilinear translational movement of the cathode towards the anode making it possible to obtain a minimum inter-electrode distance of 10 to 200 μm, so as to achieve the anodic dissolution of the γ-γ″ nickel-based superalloy workpiece;
F—recovering the machined workpiece obtained in step E).

8. The process as claimed in claim 7 , wherein step E) is implemented in static mode, without rectilinear translational movement of the cathode towards the anode.

9. The process as claimed in claim 7 , wherein step E) is implemented in dynamic mode, with rectilinear translational movement of the cathode towards the anode.

10. The process as claimed in claim 7 , wherein step E) is implemented with oscillation of the cathode.

Assignees

• Safran Aircraft Engines
• Univ De Lorraine
• Centre Nat Rech Scient

Inventors

• Msakni Malouche Mariem
• Lecomte Janvier
• Rancic Mickael
• Stein Nicolas
• Boulanger Clotilde

Classifications

• B23H3/08 Primary

  Working media · CPC title

• C25F3/22

  of heavy metals · CPC title

• C25D5/18

  Electroplating using modulated, pulsed or reversing current · CPC title

• B23H9/10

  Working turbine blades or nozzles · CPC title

• C25D3/562

  containing more than 50% by weight of iron or nickel or cobalt · CPC title