The present disclosure relates generally to a remanufactures process and, more particularly, to a repair process for aluminum fan blades.

Gas turbine engines, such as those that power modern commercial and military aircraft, generally include a fan section, a compressor section to pressurize an airflow, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases.

The fan section often includes aluminum fan blades designed with a multi-layer polyurethane erosion coating to protect both sides of the airfoil from operational erosion and subsequent corrosion. The erosion coatings sustain erosion, FOD and local damage in service, but there is only minimal repair capability for these coatings.

A method according to one disclosed non-limiting embodiment of the present disclosure e.g. a method for repairing a component or a multi-layer polyurethane erosion coating can include applying a Sol-Gel layer onto a substrate and applying an erosion coating layer over the Sol-Gel layer.

A further embodiment of the present disclosure may include, wherein the method is applied to a local area.

A further embodiment of the present disclosure may include, wherein the method provides for a local repair to a fan blade.

A further embodiment of the present disclosure may include applying a paint primer to the Sol-Gel layer prior to applying the erosion coating layer.

A component according to one disclosed non-limiting embodiment of the present disclosure can include a local area with a Sol-Gel layer over an aluminum substrate.

A further embodiment of the present disclosure may include an erosion coating is over the Sol-Gel layer.

A further embodiment of the present disclosure may include a paint primer between the Sol-Gel layer and the erosion coating layer.

A further embodiment of the present disclosure may include, wherein the component is a fan blade.

A further embodiment of the present disclosure may include, wherein the paint primer is a corrosion inhibiting paint primer.

A further embodiment of the present disclosure may include, wherein the coating is a multi-layer polyurethane erosion coating

A further embodiment of the present disclosure may include a component obtained by the methods as herein described.

The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation of the invention will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting.

Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:

• Figure 1 is a general schematic view of an exemplary component as a representative workpiece;
• Figure 2 is an expanded cross section of the component; and
• Figure 3 is an expanded cross section of a repair to the component.

Figure 1 schematically illustrates a general perspective view of an exemplary component 20, e.g., a fan blade with a multi-layer polyurethane erosion coating for a gas turbine engine. It should be appreciated that although a particular component type is illustrated in the disclosed non-limiting embodiment, other components with a multi-layer polyurethane coating will also benefit herefrom.

With reference to Figure 2, a cross-section of the component 20 is illustrated for an aluminum substrate 30 such as a 2000, 6000, or 7000 series aluminum with a multi-layer coating 35. The coating 35 includes a phosphoric acid anodizer layer 40, an epoxy bond primer 50 as a corrosion inhibitor, a paint primer 60, and an erosion coating 70 such as a urethane as the outer layer. It should be appreciated that various materials may be utilized in accords with this layer structure.

With reference to Figure 3, a local repair 100 for the component 20 may be performed on an airflow surface. That is, the local repair of damage may be performed in response to damage within the polyurethane coating stack up on the aluminum substrate 30. The local repair 100 may be initiated by abrading down to the aluminum substrate 30 or for damage that has reached down to the aluminum substrate 30. The polyurethane coating stack adjacent to the damage may be abraded, feathered or otherwise prepared and cleaned with, for example aluminum oxide and an acetone wipe.

Next, a Sol-Gel layer 110 is applied over the aluminum substrate 30 to react with the aluminum substrate 30 and thereby provide a stable surface. The Sol-Gel layer 110 may be provided with a 1hour room temperature cure. The Sol-Gel layer 110 process involves conversion of monomers into a colloidal solution (sol) that acts as the precursor for an integrated network (or gel) of either discrete particles or network polymers. The Sol-Gel layer 110 does not adversely react or effect adjacent coatings layers 40-70 such that masking is not otherwise required.

Next, the paint primer 60 is applied over the Sol-Gel layer 110. The Sol-Gel layer 110 significantly improves the adhesion of paint primers within the coating stack up. Finally, the erosion coating 70 is applied over the paint primer 60 to finalize the local repair 100.

The use of the terms "a," "an," "the," and similar references in the context of description (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or specifically contradicted by context. The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. It should be appreciated that relative positional terms such as "forward," "aft," "upper," "lower," "above," "below," and the like are with reference to the normal operational attitude of the vehicle and should not be considered otherwise limiting.

Although the different non-limiting embodiments have specific illustrated components, the embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments.

It should be appreciated that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be appreciated that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, it should be appreciated that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present disclosure.

The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be appreciated that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.