FIG. 4 is a scanning electron microscopy (SEM) image of Rice University Ni-coated F-SWNT manufactured by heat induction
Rice University materials engineers have produced new composite materials that include using carbon nanotubes (CNTs) in a titanium (Ti) metal-matrix. The CNTs used are single wall carbon nanotubes (SWNTs). This new composite material is considered to be advantageous over pure Ti in many aspects. Prior art methods used to create metal/CNT composites have not been shown to be successful in metal atmospheres capable of forming carbides.
Rice University methods allow for the successful creation of new composites with metal-coated CNT reinforcements in a matrix capable of forming carbides from the CNT, wherein such carbide formation would otherwise destroy the basic nanotube structure. The creation of this new material allows for improved properties over those of pure Ti. The production steps are part of the successful creation of the new composite material. The creation of this particular material makes it unique compared to other metal matrix composites.
The new material(s) derived from the Rice University new nanofabrication process can be used as an improvement for any past, present, or future application that uses titanium and titanium alloys.
The new material(s) derived from the Rice University new nanofabrication process can be used as an improvement for any past, present, or future application that uses titanium and titanium alloys.
In U.S. Patent Application 20100015002, the processing of single-walled carbon nanotube metal-matrix composites manufactured by an induction heating method is disclosed by Rice University Chair of the Department of Mechanical Engineering. and Material Science Enrique V. Barrera, Professor in Mechanical Engineering. Heat Transfer and Fluid Flow, Manufacturing and Processing Yildiz Bayazitoglu and Kenneth Wilson.
Matrix-reinforced materials science continues to be a rapidly evolving field of investigation both from the point of view of fundamental research as well as its industrial application. Metals can display a wide range of outstanding qualities. Certain metals, such as copper, display excellent thermal and electrical conductivities, but poor strength. Other metals like titanium display remarkable strength and corrosion resistance, but poorer thermal and electrical conductivities. Individual single wall carbon nanotubes (SWNTs) display superior qualities to all metals, characteristics that make them potentially perfect additives for metals and for the creation of new metal composites.
Such composites, however, have generally been limited to those which comprise non-carbide forming metals because high-temperature processing of carbon nanotubes in carbide forming metals will generally lead to the destruction of the nanotubes. Accordingly, a method of making such composites which permits the incorporation of carbon nanotubes into carbide forming metal matrices, while maintaining the structural integrity of the carbon nanotubes, would be highly beneficial.
To meet needs for new carbon nanotube composites, the inventors manufactured single-wall carbon nanotubes (SWNTs) coated with a first metal; and a second metal within which the single-wall carbon nanotubes coated with a first metal are dispersed. The first metal is a non-carbide forming metal, and the second metal, which serves as a matrix, is selected from the group consisting of carbide-forming metals and non-carbide forming metals. Regarding such compositions, in some embodiments, the SWNTs are generally functionalized as fluorinated SWNTs (F-SWNTs). The nanotubes in such compositions are structurally intact. The first metal is nickel and the second metal is titanium or a titanium alloy.
Such composites, however, have generally been limited to those which comprise non-carbide forming metals because high-temperature processing of carbon nanotubes in carbide forming metals will generally lead to the destruction of the nanotubes. Accordingly, a method of making such composites which permits the incorporation of carbon nanotubes into carbide forming metal matrices, while maintaining the structural integrity of the carbon nanotubes, would be highly beneficial.
To meet needs for new carbon nanotube composites, the inventors manufactured single-wall carbon nanotubes (SWNTs) coated with a first metal; and a second metal within which the single-wall carbon nanotubes coated with a first metal are dispersed. The first metal is a non-carbide forming metal, and the second metal, which serves as a matrix, is selected from the group consisting of carbide-forming metals and non-carbide forming metals. Regarding such compositions, in some embodiments, the SWNTs are generally functionalized as fluorinated SWNTs (F-SWNTs). The nanotubes in such compositions are structurally intact. The first metal is nickel and the second metal is titanium or a titanium alloy.
The manufacturing method includes the steps of: (a) electrolessly-coating single-wall carbon nanotubes with a first metal to form metal-coated nanotubes; (b) mixing the metal-coated nanotubes with a second metal to form a mixture; and (c) heating the mixture to form a composite, wherein the first metal is a non-carbide forming metal, and wherein the second metal, which serves as a matrix, is selected from the group consisting of carbide-forming metals and non-carbide forming metals. The heating involves induction heating. Generally, such methods permit the nanotubes to survive (structurally) the processing and remain intact in the resulting composite.
FIGS. 5(a)-5(d) are SEM results of nickel-coated F-SWNTs in SWNT-titanium metal-matrix composites after manufacturing by an induction heating method.
FIG. 6 shows SEM images of (a) pure bundled SWNTs; (b) and (c) SWNTs in a titanium powder after the ball milling/incipient wetting process; (d) SWNTs in a copper powder after the ball milling/incipient wetting process.
