Cleaning compositions and methods for removing oxides from superalloy substrates

Patent metadata

Field	Value
Publication number	US-10377968-B2
Application number	US-201715619990-A
Country	US
Kind code	B2
Filing date	Jun 12, 2017
Priority date	Jun 12, 2017
Publication date	Aug 13, 2019
Grant date	Aug 13, 2019

Abstract

Methods for cleaning a superalloy substrate having engine deposits on its surface are provided. The method may include applying a permanganate solution onto the surface of the superalloy substrate, and applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate. The ferric chloride based cleaning composition includes ferric chloride and at least one of nitric acid and phosphoric acid, such as within a solvent system (e.g., an aqueous solution including water).

First claim

What is claimed is:

1. A method of cleaning a superalloy substrate having engine deposits on its surface, the method comprising:
applying an alkaline solution to the surface of the superalloy substrate;
thereafter, applying an acid solution to the surface of the superalloy substrate, wherein the acid solution comprises a citrate-based organic acid;
thereafter, applying a permanganate solution onto the surface of the superalloy substrate; and
applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate, wherein the ferric chloride based cleaning composition comprises ferric chloride and at least one of nitric acid and phosphoric acid.

2. The method of claim 1 , wherein the ferric chloride based cleaning composition comprises ferric chloride, nitric acid, and phosphoric acid.

3. The method of claim 1 , wherein the ferric chloride based cleaning composition further comprises a solvent system.

4. The method of claim 3 , wherein the solvent system comprises water.

5. The method of claim 3 , wherein the ferric chloride based cleaning composition consists of ferric chloride, nitric acid, phosphoric acid, and the solvent system.

6. The method of claim 1 , wherein the ferric chloride based cleaning composition comprises about 130 g/L to about 160 g/L ferric chloride, about 95 g/L to about 115 g/L nitric acid, and about 115 g/L to about 145 g/L phosphoric acid.

7. The method of claim 1 , wherein the ferric chloride based cleaning composition comprises about 140 g/L to about 160 g/L ferric chloride, about 95 g/L to about 115 g/L nitric acid, and about 115 g/L to about 145 g/L phosphoric acid.

8. The method of claim 1 , wherein the superalloy substrate comprises a nickel-containing base metal or a cobalt-containing base metal.

9. The method of claim 1 , further comprising:
repeating a series of applying the permanganate solution onto the surface of the superalloy substrate and then applying the ferric chloride based cleaning composition onto the surface of the superalloy substrate.

10. The method of claim 9 , wherein the permanganate solution comprises potassium permanganate, sodium permanganate, or a mixture thereof.

11. The method of claim 10 , wherein the permanganate solution further comprises sodium hydroxide.

12. The method of claim 1 , wherein the alkaline solution comprises sodium hydroxide, sodium gluconate, and a surfactant.

13. The method of claim 1 , wherein applying the ferric chloride based cleaning composition onto the surface of the superalloy substrate comprises immersing the superalloy substrate into the ferric chloride based cleaning composition.

14. A method of cleaning a superalloy substrate having engine deposits on its surface, the method comprising:
applying an alkaline solution to the surface of the superalloy substrate, wherein the superalloy substrate comprises nickel and/or cobalt-containing base metal; and
thereafter, applying an acid solution to the surface of the superalloy substrate, wherein the acid solution comprises a citrate-based organic acid;
thereafter, applying a permanganate solution onto the surface of the superalloy substrate; and
thereafter, applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate, wherein the ferric chloride based cleaning composition comprises an aqueous solution of ferric chloride, nitric acid, and phosphoric acid.

15. The method of claim 14 , wherein the ferric chloride based cleaning composition comprises about 130 g/L to about 160 g/L ferric chloride, about 95 g/L to about 115 g/L nitric acid, and about 115 g/L to about 145 g/L phosphoric acid.

16. The method of claim 14 , further comprising:
repeating a series of applying the permanganate solution onto the surface of the superalloy substrate and then applying the ferric chloride based cleaning composition onto the surface of the superalloy substrate.

17. The method of claim 16 , wherein the series is repeated for at least 5 cycles.

18. The method of claim 14 , wherein applying the ferric chloride based cleaning composition onto the surface of the superalloy substrate comprises immersing the superalloy substrate into the ferric chloride based cleaning composition.

19. A method of cleaning a superalloy substrate having engine deposits on its surface, the method comprising:
applying an alkaline solution to the surface of the superalloy substrate, wherein the alkaline solution comprises sodium hydroxide, sodium gluconate, and a surfactant;
thereafter, applying an acid solution to the surface of the superalloy substrate;
thereafter, applying a permanganate solution onto the surface of the superalloy substrate; and
applying a ferric chloride based cleaning composition onto the surface of the superalloy substrate, wherein the ferric chloride based cleaning composition comprises ferric chloride and at least one of nitric acid and phosphoric acid.

20. The method of claim 19 , wherein the ferric chloride based cleaning composition comprises ferric chloride, nitric acid, phosphoric acid, and a solvent system.

Assignees

• Gen Electric

Inventors

• Brooks William Clarke
• Huron Eric Scott
• Powers John Matthew
• Goodall Ian Thomas
• Dolley Jr Evan Jarrett
• Trider David Edward
• Bolukoglu Zeynep
• Ulutas Doga
• Aydin Tugba

Classifications

• C11D11/0029

  Chemistry & Metallurgy · mapped topic

• F01D25/002

  Cleaning of turbomachines · CPC title

• F05D2300/175

  Superalloys · CPC title

• C23G1/085

  solutions containing HNO3 · CPC title

• C11D3/042

  Acids · CPC title