Nanotube-containing composite bodies, and methods for making same

Abstract

A composite material featuring comminuted or otherwise well dispersed and separated nanotubes reinforcing a matrix featuring metal, ceramic and / or polymer. In a preferred embodiment, the nanotubes feature elemental carbon, and the composites can be produced using a molten silicon metal infiltration technique, which may be pressurized or not, for example, a siliconizing or a reaction-bonding process. In this preferred embodiment, carbon nanotubes may be prevented from chemically reacting with the silicon infiltrant by an interfacial coating disposed between the carbon nanotubes and the infiltrant. A reaction-bonded composite body containing even a small percentage of carbon nanotubes possessed a significant increase in electrical conductivity as compared to a reaction-bonded composite not containing such nanotubes, reflecting the high electrical conductivity of the nanotubes. When the nanotubes are well dispersed throughout the preform, mechanical property enhancements start to become noticeable, such as fracture toughness enhancement.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a Continuation-in-Part of Commonly Owned U.S. patent application Ser. No. 10 / 832,823, filed on Apr. 26, 2004. The entire contents of this commonly owned patent application are expressly incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] This invention was made with Government support under Contract No. FA9453-04-M-0255 awarded by the U.S. Air Force Research Laboratory. The Government has certain rights in the invention.BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] The present invention relates to metal and / or ceramic containing composite materials featuring a particular kind of fibrous reinforcement. In particular, the invention relates to composites having a matrix featuring metal, ceramic and / or polymer, and being reinforced with nanotubes, and preferably carbon nanotubes. [0005] 2. Discussion of Related Art [0006] It has been known for a long time to a...

AI Technical Summary

Benefits of technology

[0037] It is an object of this invention to produce composite materials that are tougher and / or more impact resistant than similar composites without nanotubes.

Problems solved by technology

Processing was difficult, however, as the metals either tended not to wet the carbon fibers, or reacted with the carbon.

As mentioned above, glass matrix composites have been used in environments where low expansion polymer composites would be insufficiently durable.

Many of these applications, however, require high thermal conductivity, and most glasses are deficient in this area.

Another problem with glass matrix composites, though, is that they tend to be brittle.

Curiously, when the nanotube is a carbon nanotube, the matrix cannot be silicon carbide.

So far, the work on composite materials featuring carbon nanotube reinforcements is still relatively scant.

There, workers noted that one of the problems associated with the carbon nanotubes was in properly dispersing them in the polymer matrix.

The production of a composite material containing both carbon nanotubes and metal, particularly molten metal, is even more of a challenge.

While a coating on a typical carbon fiber may be adequately protective against chemical reaction with a metal, particularly a molten metal, one cannot simply scale the coating / fiber system down to the typical size of a carbon nanotube because the coating will likely have insufficient thickness to be protective of the underlying nanotube.

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