NOVELTY - Production of composite comprises contacting a metal substrate with a feedstock to form nanotubes; and using the composite in devices for electrical energy storage and retrieval, gas adsorption and desorption, sensing, catalysis, heat transfer, fuel cells, solar collectors or medical prosthesis.    USE - For producing composite for use in devices for electrical energy storage and retrieval (battery electrode or ultracapacitor electrode); gas adsorption and desorption (hydrogen storage and catalysis device including catalytic converter or cracking catalyst for oil production); sensing (chemical sensor); catalysis; heat transfer (heat sinks, heat pipes, heat exchangers, spray cooling apparatus, single-phase convection apparatus, or two-phase convection apparatus); fuel cells; solar collectors; or medical prosthesis (claimed); or heat transfer and thermal control, fuel cell catalytic reformers, electronics and semiconductors, and tribological wear and protective coatings.    ADVANTAGE - The method allows nanotubes to be grown directly onto metal substrates containing catalysts which eliminates the need to separate the nanotubes prior to deposition or to combine the nanotubes with other substrates used in an application. It does not require the use of other support materials such as alumina or silica which are commonly used. It does not require the deposition of metal catalysts by solution or plasma or ion implantation. The growth of carbon nanotubes directly onto metal substrates provides a production cost reduction since no additional materials (e.g. catalysts, supports, and digestion media) are needed.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method comprising directly coating a copper alloy with carbon nanotubes to form a composite, and coating the composite with a thermoset or thermoplastic polymer.    DESCRIPTION OF DRAWING(S) - The figure is a schematic cross-sectional view of a batch coating apparatus for carrying out the inventive process.    Carbon feedstock and purge gases (1-4)    Substrate (6)    Furnace (9)