CHEMICAL PROCESS FOR MATIFICATION

• US 20200131646A1
• Filed: 10/25/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Safran Aircraft Engine Company
• Original Assignee: Safran Aircraft Engine Company
• Inventors: Saget, Pierre-Joseph Xavier Herve
• Granted Patent: US 11,280,007 B2
• Time in Patent Office: Days
• CPC Class Codes: C23F 1/26 for etching refractory metals
• CPC Class Codes: C23G 1/106 refractory metals
• CPC Class Codes: C23G 1/14 with alkaline solutions
• CPC Class Codes: F01D 25/002 Cleaning of turbomachines

Abstract

The invention relates to a method for mattifying a turbine engine part (10) comprising a metal material, the method comprising a step of immersing said part in a chemical bath (14) for mattifying said metal part (10), the bath (14) comprising at least sodium fluoride (NaF) and hydrofluoric (HF) acid, characterised in that the immersion step lasts between 2 and 15 minutes.

Claims

1. Method for mattifying a turbine engine part (10) comprising a metal material, the method comprising a step of immersing said part in a chemical bath (14) for mattifying said metal part (10), the bath (14) comprising at least sodium fluoride (NaF) and hydrofluoric (HF) acid, characterised in that the immersion step lasts between 2 and 15 minutes.

2. Method according to claim 1, characterised in that the immersion step is configured so as to create a homogenous dissolution of the metal material over a thickness of around 3 to 10 μ

m, and in that the part (10) is enriched with a minimum quantity of dihydrogen (H₂).

3. Method according to claim 1, characterised in that the metal material of the part (10) comprises titanium (Ti), a titanium alloy and/or titanium oxides (TiO₂).

4. Mattifying method according to claim 1, characterised in that the dissolved material thickness is 5 μ

m.

5. Mattifying method according to claim 1, characterised in that the enriching with dihydrogen (H₂) of the part (10) is around 15 ppm.

6. Mattifying method according to claim 1, characterised in that the part (10) has, on the surface, a titanium oxide (TiO₂) and alpha case layer, the homogenous dissolution making is possible to remove the titanium oxide (TiO₂) and alpha case layer.

7. Mattifying method according to claim 6, characterised in that the homogenous dissolution occurs successively and/or at the same time according to two of the following chemical reactions:

NaF+H₂SO₄═

FH+NaHSO₄ 

 

(1)

TiO₂+6HF→

TiF₆H₂+H₂O. 

 

(2)

8. Mattifying method according to claim 1, characterised in that it comprises a step of installing at least one part (10) to be mattified in a tool (12) prior to the step of immersing in the chemical bath.

9. Mattifying method according to claim 8, characterised in that the temperature of the chemical bath during the immersion step is of between 15 and 30°

C.

10. Mattifying method according to claim 9, characterised in that it comprises the following steps:

a step of preparing the surface of the at least one part (10), and

a step of rinsing the part (10).

11. Mattifying method according to claim 10, characterised in that the step of preparing the surface of the at least one part (10) is carried out before the immersion step and comprises:

a step of degreasing the part for 10 minutes at a temperature of between 45 and 55°

C., during which the tool is immersed in an alkaline bath,

a first step of passive rinsing of 60 seconds at ambient temperature, during which the tool is immersed in a water bath,

a first step of current rinsing of 120 seconds at ambient temperature, during which the tool is immersed in a running water bath or water-sprayed.

12. Mattifying method according to claim 8, characterised in that the rinsing step is carried out after the immersion step and comprises:

a second passive rinsing step of 60 seconds at ambient temperature, during which the tool (12) is immersed in a water bath,

a second current rinsing step of 120 seconds at ambient temperature, during which the tool (12) is immersed in a running water bath or water-sprayed,

a final hot rinsing step of 45 seconds at a temperature greater than or equal to 70°

C., during which the tool (12) is immersed in a running water bath or water-sprayed.