Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Scrim – Woven scrim
Reexamination Certificate
1997-10-20
2001-04-24
Copenheaver, Blaine (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Scrim
Woven scrim
C442S008000, C442S228000, C442S229000, C442S238000, C442S377000, C442S380000
Reexamination Certificate
active
06221795
ABSTRACT:
This application claims the priority of German patent application 196 42 983.8, filed Oct. 18, 1996, the disclosure of which is expressly incorporated herein by reference and which can be relied on to make and use aspects of this invention.
The invention relates to a composite material comprising a substrate and a cover layer. Metallic, ceramic or glass-type particles are embedded in the cover layer, which also comprises metallic fibers and/or threads. Furthermore, the invention relates to a process for manufacturing a composite material.
BACKGROUND AND SUMMARY OF THE INVENTION
Nowadays, numerous products and product parts are made of composite materials or composites. In order to achieve sufficient strength and stability under load while at the same time keeping the weight low, a fiber composite construction is often used. Under high mechanical loads, however, customary fiber composite parts have a low resistance to abrasion. This limits the durability of these composites and parts made of them.
Components, and particularly blades, made of a fiber-reinforced composite material, which are exposed to a fluid flow in turbo-engines, are particularly endangered by erosion because of abrasive particles in the fluid flow media and by thermal stress. For protecting power unit components, it is suggested, in German Patent Document DE-OS 43 43 904, to apply an erosion-resistant inorganic lacquer layer to the component. Although by means of this process the components can also be repaired, the permanence of the adhesion of the lacquer layer on the components presents a problem. Frequently, during the useful lifetime of the component, the application of the lacquer layer must be repeated.
As an alternative, German Patent Document DE-PS 42 08 842 discusses an erosion protection for helicopter rotor blades made of fiber-reinforced plastic materials. This is achieved through, at the critical points, a rotor blade being covered by a glued-on metal sheet, which is coated with particles of metal compounds. The problem of permanence of adhesion between the glued-on metal sheet and the composite fiber structure situated underneath also exists in this case.
A development by the inventors relates to a blade for a turbo-engine in which at least one blade exposed to the flow is constructed as a composite with layers of fiber-reinforced plastic material and with at least one metallic cover layer, which is applied to part of the surface or to the whole surface, as a protection against erosion. This cover layer has metallic fibers or threads, which are connected with the fiber-reinforced plastic material of the adjoining layers by way of the same synthetic resin binder. In addition, the blade may be coated, over part of its surface or over its whole surface, by an erosion-resistant protective layer, such as a temperature-resistant lacquer or a thermoplastic foil.
In addition to the erosion resistance because of the use of metallic fibers or threads in the cover layer, a tolerance to defects is also reached as a result of the plurality of mutually connected fibers or threads. As a further advantage, for example, in the case of local damage to the cover layer, the automatic spreading of the damage or a detaching of the cover layer is avoided, which may occur, for example, in the case of glued-on metal sheets as the cover layer, discussed above. The advantageous high adhesiveness of the cover layer on the substrate situated underneath is ensured by the joint synthetic resin binder, which connects the fiber-reinforced plastic layers and the cover layers to one another as well as with one another. Furthermore, the electric conductivity of the metallic fibers or threads results in a lightning protection, which is advantageous, for example, for rotor blades or propellers. However, it is desirable to further improve the resistance to abrasion and erosion of a correspondingly constructed composite for applications in the case of extremely stressed components.
For this purpose, the invention provides a composite comprising a substrate having at least one fiber layer, and a cover layer, which adjoins and which, adjacent to the at least one fiber layer, has metallic fibers and/or threads. The at least one fiber layer of the substrate and the metallic fibers and/or threads of the cover layer are saturated with binder or at least one binder composition so that, as a result, the substrate and the cover layer are formed and connected. The improvement of the abrasion resistance to composites constructed according to the present invention is achieved, inter alia, by embedding metallic, ceramic or glass-type particles in the cover layer in the area of the metallic fibers and/or threads.
Embedding particles, according to the invention, into the area of the metallic fibers and/or threads of the cover layer improves the resistance to abrasion. In addition and as another advantage, the added particles result in lower or higher coefficients of friction that can be adjusted in connection with such a composite depending on the application requirement. The electric conductivity of the cover layer is advantageously maintained because of the metallic fibers and/or threads therein. Furthermore, the abrasive behavior of this cover layer is improved in comparison to earlier constructions.
In preferred embodiments of the invention, it is provided that the substrate contains a plurality of fiber layers and/or is a fiber-reinforced plastic material and/or the at least one fiber layer of the substrate completely or partially contains non-metallic fibers.
Generally, in addition to one or several areas with/of metallic fibers and/or threads, the cover layer may also have other components or sections. The cover layer is preferably formed of a substantial amount of the metallic fibers and/or threads, and with the embedded particles and the binder.
Within the scope of another preferred aspect of the composites of the invention, it is provided that the fiber layer and the metallic fibers and/or threads of the cover layer are saturated and connected by means of the same binder. However, as a function of the usage demands of the composite, different binders can be used in the layers. For example, resin, particularly synthetic resin, is suitable for use as the binder or in binder compositions.
The metallic fibers and/or threads of the cover layer of the composite according to the invention may form a mesh and/or a woven structure. However, it is particularly advantageous for these fibers and/or threads to be present in the form of felt.
According to the desired characteristics of the cover layer, metallic, ceramic and/or glass-type particles can be used. In particular, the particles may contain TiC, TiN, TiAl, Fe, steel, Ni, Si, metal alloys, diamond, glass and compounds therewith as well as combinations thereof. With respect to their structural shape and geometry, the particles may be solid, porous or hollow.
In order to facilitate and optimize the introduction of the particles into the area of the metallic fibers and/or threads of the cover layer, it is advantageous for the particles to be components of a carrier medium which surrounds the metallic fibers and/or threads of the cover layer at least partially and/or directly. Such a carrier medium also promotes the distribution capacity and the adhesion of the particles in the area of the metallic fibers and/or threads of the cover layer. Preferred types of carrier medium are solder compounds, metal fillers, adhesive agents, such as bonding agents in particular, or thermoplastic materials.
For a distribution which is as uniform as possible and for a secure fastening of the particles in the area of the metallic fibers and/or threads of the cover layer, it is also advantageous for the particles to be completely or partially connected by means of the binder, optionally the carrier medium, by a mechanical clamping with the metallic fibers and/or the threads of the cover layer, by sintering or the HIP (hot isostatic pressing) process with the metallic fibers and/or threads of the cover layer. However
Schober Michael
Schönacher Reinhold
Sikorski Siegfried
Copenheaver Blaine
Evenson, McKeown, Edwards & Lenahan P.L.L.C.
MTU Motoren-und Turbinen-Union Muenchen GmbH
Pratt Christopher C.
LandOfFree
Composite material and process for manufacturing same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composite material and process for manufacturing same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composite material and process for manufacturing same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2500370