Antifouling layer for compressor blades

Abstract

The present invention relates to a composition for producing a coating having antifouling properties on a component of a turbomachine. The composition comprises a binder comprising at least one silicon-organic constituent, ceramic particles and a solvent, the ceramic particles comprising at least silicon dioxide and the silicon-organic constituent comprising at least alkoxysilane. In addition, the present invention relates to a process for producing a coating using such a composition and also a correspondingly produced coating and a component provided therewith.

Claims

1. A process for providing a coating having antifouling properties on a component of a turbomachine, wherein the process comprises applying to the component a coating composition which comprises a binder comprising at least one silicon-organic constituent that comprises at least one alkoxysilane, ceramic particles which comprise at least silicon dioxide, and a solvent; and subsequently curing the coating composition by a heat treatment at a temperature of from 200 C. to 350 C. for from 10 minutes to 120 minutes.

2. The process of claim 1, wherein the heat treatment is carried out at a temperature of from 250 C. to 300 C.

3. The process of claim 2, wherein the heat treatment is carried our for 15 minutes to 60 minutes.

4. The process of claim 1, wherein the ceramic particles have an average or maximum particle size of less than 4 m.

5. The process of claim 1, wherein the silicon-organic constituent further comprises one or more polysiloxanes.

6. The process of claim 1, wherein the ceramic particles further comprise one or more of aluminum oxide, titanium oxide, zirconium oxide, aluminum titanate, an aluminosilicate, feldspar, a zeolite, kaolin.

7. The process of claim 1, wherein the composition further comprises at least one fluorosilane and/or graphite.

8. The process of claim 1, wherein the composition has a solids content of from 10% by wt to 40% by wt.

9. The process of claim 8, wherein the ceramic particles are present in a concentration of from 10% by weight to 20% by weight, based on the solids content of the composition.

10. The process of claim 1, wherein the composition is applied in several sublayers.

11. The process of claim 10, wherein a first sublayer is applied using the composition and dried at room temperature and, after drying of the first sublayer, a second sublayer is applied using the composition and dried, whereafter the first and second sublayers are cured together.

12. The process of claim 1, wherein a coating thickness is from 5 m to 30 m.

13. The process of claim 1, wherein a coating thickness is from 5 m to 15 m.

14. The process of claim 1, wherein the coating has an average peak-to-valley height of not more than 2 m.

15. The process of claim 1, wherein the component is a compressor blade.

Description

DETAILED DESCRIPTION OF EMBODIMENTS

(1) The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

WORKING EXAMPLE

(2) In a working example, 620 g of an alkoxysilane is placed in a covered 2000 ml glass beaker and mixed with 200 g of butyl acetate at room temperature for one hour in the fume hood by stirring by means of a high-speed mixer. 60 g of a submicron titanium dioxide (from Sachtleben) and 65 g of a micron-sized aluminum titanate (from Alroko) and 80 g of silicon dioxide are subsequently added as powders and the mixture is stirred for a further 30 minutes. The materials can also be made up separately beforehand as a powder mixture.

(3) After reduction of the stirrer speed to 200 rpm, 15 g of graphite and 10 g of a commercial leveling additive (BYK) are added and the mixture is stirred for a further 30 minutes. After spreading of a sample on glass, which should be free of lumps, the coating material is introduced into a SATA-VLP low-pressure spray gun and sprayed onto the component at 2 bar. After drying at room temperature for one hour, the coating is baked at 250 C. for one hour. After baking, a layer thickness of about 10 m is obtained.

(4) The corresponding constituents of the composition are mixed with one another by stirring and, for example, applied to at least parts of a compressor blade of a turbomachine by spraying. The corresponding compressor blade is exposed at 300 C. in an oven for one hour in order to cure the coating.

(5) The finished coating, which extends at least partly over the compressor blade, has, due to among other things the fine ceramic particles, a low average peak-to-valley height which gives the coated component an advantageous smoothness which both improves the antifouling properties and meets the aerodynamic requirements of a compressor blade in a turbomachine.

(6) Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.