Ceramic materials reinforced with metal and single-wall carbon nanotubes
AssigneeThe Regents of the University of California, a California corporation
InventorsJoshua D. Kuntz, Guodong Zhan, Amiya K. Mukherjee
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Abstract
High-density composites of ceramic materials, notably alumina or metal oxides in general, are formed by the incorporation of metal particles, of which niobium is a preferred example, and single-wall carbon nanotubes. The composites demonstrate an unusually high fracture toughness compared to the ceramic alone, and also when compared to composites that contain either the metal alone or single-wall carbon nanotubes alone. The two additives thus demonstrate a synergistic effect in improving the toughness of the ceramic.
Claims29
A high-performance ceramic material comprising (i) grains of a metal selected from the group consisting of aluminum, chromium, copper, molybdenum, niobium, nickel, titanium, tungsten, and alloys of such metals, and (ii) single-wall carbon nanotubes, components (i) and (ii) both being substantially uniformly dispersed throughout a matrix of ceramic grains to form a continuous fused mass having a density of at least 99% relative to a volume-averaged theoretical density.
A process for forming a high-performance ceramic material, said process comprising consolidating a mixture of ceramic particles of less than about 100 nm in diameter, metallic particles of less than about 100 microns in diameter, and single-wall carbon nanotubes into a continuous mass by compressing said mixture while passing an electric current through said mixture, said metallic particles being a member selected from the group consisting of aluminum, chromium, copper, molybdenum, niobium, nickel, titanium, tungsten, and alloys of such metals.
A process for forming a high-performance alumina-based ceramic material, said process comprising:
- (a) forming a mixture comprising alumina powder, niobium powder, and single-wall carbon nanotubes in which said niobium powder constitutes from about 2% to about 15% by volume of said mixture and said single-wall carbon nanotubes constitute from about 2% to about 15% by volume of said mixture;
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- (b) consolidating mixture into a continuous mass by compressing said mixture at a pressure of from about 40 MPa to about 100 MPa while exposing said mixture to a pulsed direct current of from about 500 A/cm2 to about 5,000 A/cm2.
Dependencies are inferred from the claim text.