A method for surface preparation of composite substrates prior to adhesive bonding. A curable surface treatment layer is applied onto a curable, resin-based composite substrate, followed by co-curing. After co-curing, the composite substrate is fully cured but the surface treatment layer remains partially cured. The surface treatment layer may be a resin film or a removal peel ply composed of resin-impregnated fabric. After surface preparation, the composite substrate is provided with a chemically-active, bondable surface that can be adhesively bonded to another composite substrate to form a covalently-bonded structure.

A composite prepreg and a fiber-reinforced plastic molded body are described that are excellent in secondary weldability with another member and exhibit excellent handleability and reinforcing characteristics, where the composite prepreg in which reinforcing fibers are impregnated with a thermoplastic resin and a thermosetting resin, and a thermoplastic resin layer and a thermosetting resin layer that form an interface and joined to each other are formed, wherein the thermoplastic resin layer is present on at least one surface of the composite prepreg, and the thermoplastic resin layer contains continuous reinforcing fibers.

Disclosed is a method of resistance welding between composite articles. A conductive element is provided between faying surfaces, having a plurality of lower resistivity electrode portions spaced apart along the length of the contact area between the composite articles. The electrode portions can be used to spot weld across the electrode portions, and along a longitudinal portion of the conductive element between the electrode portions by application of an electrical current. Also disclosed are apparatus for use in the resistance welding methods and composite articles and structures and elements incorporating the conductive element.

The invention relates to a method for the application of heating mats (10) on a wing/blade of a wind power station or other devices for the purpose of achieving deicing also during operation when necessary. Temperature measurement and de-icing take place by means of pulsed current to the heating mat (10). The invention also relates to an arrangement.

A method for forming a composite part of a gas turbine engine. The method includes assembling the composite part of a first composite material and a second composite material. The second composite material defines an outer surface of the composite part, and is selected to be curable at a cure temperature generated by heat from operation of the engine. The first composite material is selected to have an operating temperature limit less than the cure temperature. The method includes placing the composite part within the engine so that, in use, the second composite material is cured by exposure to the heat generated from operation of the engine. The second composite material thermally shields the first composite material from the heat generated from operation of the engine. The method includes operating the engine to cure the second composite material.

Disclosed is a method of resistance welding between composite articles. A conductive element is provided between faying surfaces, having a plurality of lower resistivity electrode portions spaced apart along the length of the contact area between the composite articles. The electrode portions can be used to spot weld across the electrode portions, and along a longitudinal portion of the conductive element between the electrode portions by application of an electrical current. Also disclosed are apparatus for use in the resistance welding methods and composite articles and structures and elements incorporating the conductive element.

A method for preparing a pre-bond surface of a composite structure includes the steps of: (1) separating a peel ply, co-cured with a composite substrate, from the composite substrate; and (2) transferring an identifiable marking agent from the peel ply to the composite substrate upon separation of the peel ply from the composite substrate. Residue of the peel ply, transferred from the peel ply to the composite substrate upon separation of the peel ply from the composite substrate, is layered on the identifiable marking agent.

A method for surface preparation of composite substrates prior to adhesive bonding. A curable surface treatment layer is applied onto a curable, resin-based composite substrate, followed by co-curing. After co-curing, the composite substrate is fully cured but the surface treatment layer remains partially cured. The surface treatment layer may be a resin film or a removal peel ply composed of resin-impregnated fabric. After surface preparation, the composite substrate is provided with a chemically-active, bondable surface that can be adhesively bonded to another composite substrate to form a covalently-bonded structure.

A part made of a fiber-reinforced composite material includes a structure made from a set of fibers supported in a thermosetting resin and a peel ply across all or part of the outer surface of the structure. The part has a gradient of polymerization at the interface between the structure and the peel ply. Also, methods for making such a part and methods for bonding such parts.

A method for manufacturing of a part made of composite material including pre-compacting to a predetermined shape of a mixture of a first thermosetting resin with discontinuous long fibers so as to form a first preform, pre-curing the first preform until an intermediate conversion stage corresponding to a solidification of said first resin, contacting the first preform with a second preform including a fiber structure of continuous fibers impregnated with a second thermosetting resin, polymerizing the first and second preforms so as to form a part made of composite material including a body made of composite material including reinforcement made of continuous fibers consolidated by an organic matrix provided with a portion made of composite material including reinforcement made of discontinuous long fibers consolidated by an organic matrix.