University of California

Guodong Zhan

Amiya K Mukherjee

Joshua D Kuntz

Julin Wan

Subhash H Risbud

Ceramic materials are converted to materials with anisotropic thermal properties, electrical properties, or both, by forming the ceramics into composites with carbon nanotubes dispersed therein and uniaxially compressing the composites in a direction in which a lower thermal or electrical conductivity is desired.

Anisotropic thermal and electrical applications of composites of ceramics and carbon nanotubes

Optical windows for protecting infrared sensing instruments are manufactured from nano-sized crystallites by compressing the crystallites into a continuous mass under high pressure in the presence of a pulsed electric current, preferably one produced by spark plasma sintering. The resulting materials have excellent optical and mechanical properties that make them favorable as replacements for the conventional single-crystal sapphire.

Polycrystalline optical window materials from nanoceramics

Ceramic materials are converted to materials with anisotropic thermal properties by forming the ceramics into composites with carbon nanotubes dispersed therein and uniaxially compressing the composites in a direction in which a lower thermal conductivity is desired.

Anisotropic thermal applications of composites of ceramics and carbon nanotubes

A nano-sized powder of barium titanate is compacted and sintered by spark plasma sintering under conditions creating a high heating rate to achieve a densified material that demonstrates superior permittivity.

High-density barium titanate of high permittivity

Composite materials formed of a matrix of fused ceramic grains with single-wall carbon nanotubes dispersed throughout the matrix and a high relative density, notably that achieved by electric field-assisted sintering, demonstrate unusually high electrical conductivity in combination with high-performance mechanical properties including high fracture toughness. This combination of electrical and mechanical properties makes these composites useful as electrical conductors in applications where high-performance materials are needed due to exposure to extreme conditions such as high temperatures and mechanical stresses.

Ceramic materials reinforced with single-wall carbon nanotubes as electrical conductors

Composites of ceramic materials, notably alumina or metal oxides in general, with single-wall carbon nanotubes are consolidated by electric field-assisted sintering to achieve a fully dense material that has an unusually high fracture toughness compared to the ceramic alone, and also when compared to composites that contain multi-wall rather than single-wall carbon nanotubes, and when compared to composites that are sintered by methods that do not include exposure to an electric field.

Growing community of inventors

Davis, CA, United States of America

Guodong Zhan