Electrolyte for electrochemical machining of gamma-gamma prime nickel-based superalloys

Patent metadata

Field	Value
Publication number	US-11548085-B2
Application number	US-201917290936-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Dec 17, 2018
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

An electrolyte for electrochemical machining of a γ-γ′ nickel-based superalloy includes NaNO 3 at a content of between 10 and 50% by weight relative to the total weight of the electrolyte; an additive chosen from KBr, NaBr, KI, NaI and mixtures thereof, in an additive/NaNO 3 molar ratio of between 1 and 15; optionally an ethylenediaminetetraacetic acid-based complexing agent at a content of between 1 and 5% by weight relative to the total weight of the electrolyte at a pH of between 6 and 12; optionally an anionic surfactant at a content of between 1 and 5% by weight relative to the total weight of the electrolyte; optionally NaOH to obtain the appropriate pH; and an aqueous solvent.

First claim

The invention claimed is:

1. An electrolyte for an electrochemical machining of a γ-γ′ nickel-based superalloy, comprising
NaNO 3 in a content of between 10% and 50% by weight relative to the total weight of the electrolyte;
an additive selected from the group consisting of KBr, NaBr, KI, NaI and mixtures thereof in an additive/NaNO 3 molar ratio of between 1 and 15;
optionally, a complexing agent based on ethylenediaminetetraacetic acid in a content of between 1% and 5% by weight relative to the total weight of the electrolyte at a pH of between 6 and 12;
optionally, an anionic surfactant in a content of between 1% and 5% by weight relative to the total weight of the electrolyte;
optionally, NaOH to obtain the appropriate 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 additive is KBr.

6. The electrolyte as claimed in claims 1 , comprising the complexing agent based on ethylenediaminetetraacetic acid.

7. The electrolyte as claimed in claim 6 , wherein the complexing agent is ethylenediaminetetraacetic acid.

8. 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).

9. A process for a 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).

10. The process as claimed in claim 9 , wherein step E) is implemented in static mode, without rectilinear translational movement of the cathode towards the anode.

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

12. The process as claimed in claims 9 , 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

• C25D3/562

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

• C25F3/22

  of heavy metals · CPC title

• B23H9/10

  Working turbine blades or nozzles · CPC title