Method for depositing a corrosion-protection coating from a suspension

Patent metadata

Field	Value
Publication number	US-10227684-B2
Application number	US-201414767803-A
Country	US
Kind code	B2
Filing date	Feb 4, 2014
Priority date	Feb 13, 2013
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

Process for depositing a coating on a substrate having at least one cavity, comprising a step of mixing ground powders of an activating agent and a powder of the metal or of the alloy to be deposited on the substrate that were ground in step a) and a liquid so as to form a suspension, and a step of applying the suspension to the portion of the substrate to be coated.

First claim

What is claimed is:

1. A process for depositing a coating on a substrate having at least one cavity of minimum equivalent diameter e cm , comprising the following successive steps:
a) grinding a powder of an activating agent and a powder of a metal or of an alloy to be deposited on the substrate, said grinding being carried out so as to obtain only particles having an equivalent diameter d such that d≤e cm /10;
b) mixing the ground powders and a liquid so as to form a suspension;
c) pickling the portion of the substrate to be coated;
d) applying the suspension to the pickled portion to provide a substrate-suspension assembly;
e) heating the substrate-suspension assembly to a temperature of between 150° C. and 400° C. and for a duration of between 20 and 60 minutes so as to at least partly eliminate the liquid;
f) further heating the substrate-suspension assembly resulting from step e) to a temperature of between 500° C. and a melting point of a least refractory element of the metal or of the alloy to be deposited and for a duration of between 1 and 10 hours so as to react the activating agent and the metal or the alloy to be deposited, completion of step f) resulting in production of a substrate-coating assembly and pulverulent residues;
g) eliminating the pulverulent residues from the substrate-coating assembly; and
a last step of heating the substrate-coating assembly at a temperature of between 900° C. and 1200° C. and for a duration of between 1 and 5 hours.

2. The process of claim 1 , wherein application of the suspension to the pickled portion is carried out by immersing the substrate in the suspension, by injecting the suspension into the at least one cavity of the substrate, or by brush application of the suspension to the at least one cavity of the substrate.

3. The process of claim 1 , wherein step g) of eliminating the residues is carried out by vibration or washing with aqueous solutions.

4. The process of claim 1 , wherein the substrate is selected from metallic substrates, substrates made of alloy(s) or made of superalloy(s), composite substrates comprising one or more metals and/or alloy(s) and/or superalloy(s) containing Ni in order to react with Al deposited and form NiAl.

5. The process of claim 1 , wherein the substrate is a metallic heat exchanger.

6. The process of claim 1 , wherein step e) is carried out under an atmosphere that is renewed every x minutes with 1 min≤x≤20 min.

7. The process of claim 1 , wherein step f) is carried out under a static inert gas atmosphere.

8. The process of claim 7 , wherein the inert gas is argon.

9. The process of claim 8 , wherein in step b) at least one organic compound is added to the mixture.

10. The process of claim 9 , wherein the at least one organic compound is selected from the group consisting of binders, lubricants and dispersants.

11. The process of claim 10 , wherein said process further comprises, between step e) and step f), a step of heating the substrate-suspension assembly resulting from step e) to a temperature of between 400° C. and a melting point of a least refractory element of the metal or of the alloy to be deposited and for a duration of between 1 and 10 hours so as to eliminate or degrade the at least one organic compound.

12. The process of claim 11 , wherein said step of heating the substrate-suspension assembly resulting from step e) is carried out under an atmosphere that is renewed every x minutes with 1 min≤x≤20 min.

Assignees

• Air Liquide
• Centre Nat Rech Scient
• Univ De Lorraine

Inventors

• Richet Nicolas
• Mazet Thierry
• Vilasi Michel
• Mathieu Stephane

Classifications

• C23C4/12

  characterised by the method of spraying · CPC title

• C23C14/22

  characterised by the process of coating · CPC title

• C23C10/60

  After-treatment · CPC title

• C23C10/20

  only one element being diffused · CPC title

• C23C2/04 Primary

  characterised by the coating material · CPC title