Invented by Soon Hyung Hong, Seung Il Cha, Kyung Tae Kim, Kyong Ho Lee, Chan Bin MO, Korea Advanced Institute of Science and Technology KAIST

The market for ceramic nanocomposite powders reinforced with carbon nanotubes (CNTs) is experiencing significant growth due to their unique properties and wide range of applications. These advanced materials offer improved mechanical, electrical, and thermal properties, making them highly desirable in various industries such as aerospace, automotive, electronics, and energy. Ceramic nanocomposites are materials that combine ceramic particles with nanoscale reinforcements, such as CNTs. The addition of CNTs enhances the mechanical strength, toughness, and thermal stability of the ceramic matrix, resulting in improved performance and durability. These materials have the potential to replace traditional ceramics in many applications, offering superior properties and performance. One of the key advantages of ceramic nanocomposites reinforced with CNTs is their exceptional mechanical properties. The high aspect ratio and exceptional strength of CNTs provide reinforcement to the ceramic matrix, resulting in materials with improved fracture toughness and resistance to cracking. This makes them ideal for applications that require high strength and durability, such as structural components in aerospace and automotive industries. In addition to their mechanical properties, ceramic nanocomposites reinforced with CNTs also exhibit excellent electrical and thermal conductivity. The unique structure of CNTs allows for efficient electron and heat transfer, making these materials suitable for applications in electronics, thermal management, and energy storage. They can be used as conductive fillers in polymer composites, enhancing their electrical and thermal conductivity while maintaining their lightweight and flexibility. The fabrication process of ceramic nanocomposite powders reinforced with CNTs involves several steps. Firstly, the CNTs are functionalized to improve their dispersion and bonding with the ceramic matrix. This is typically achieved through chemical treatments or functionalization techniques, which modify the surface of the CNTs to enhance their compatibility with the ceramic particles. Once the CNTs are functionalized, they are mixed with the ceramic powders using various techniques such as ball milling, ultrasonication, or spray drying. The goal is to achieve a homogeneous distribution of CNTs within the ceramic matrix, ensuring uniform reinforcement throughout the material. The mixture is then compacted into a desired shape, followed by sintering at high temperatures to consolidate the powders and form a dense ceramic nanocomposite. The market for ceramic nanocomposite powders reinforced with CNTs is expected to witness significant growth in the coming years. The increasing demand for lightweight, high-performance materials in industries such as aerospace, automotive, and electronics is driving the adoption of these advanced materials. Additionally, ongoing research and development efforts are focused on improving the fabrication process and exploring new applications for these materials, further fueling their market growth. However, there are still challenges that need to be addressed in the fabrication process of ceramic nanocomposites reinforced with CNTs. Achieving a uniform dispersion of CNTs within the ceramic matrix and maintaining their structural integrity during processing can be challenging. Additionally, the cost of production and scalability of the fabrication process need to be optimized to make these materials commercially viable. In conclusion, the market for ceramic nanocomposite powders reinforced with carbon nanotubes is witnessing significant growth due to their unique properties and wide range of applications. These advanced materials offer improved mechanical, electrical, and thermal properties, making them highly desirable in various industries. The fabrication process of these materials involves several steps to achieve a uniform distribution of CNTs within the ceramic matrix. Ongoing research and development efforts are focused on improving the fabrication process and exploring new applications, further driving the market growth of these materials.

The Korea Advanced Institute of Science and Technology KAIST invention works as follows

The invention is a method for manufacturing ceramic nanocomposite particles, which contain a ceramic matrix with carbon nanotubes uniformly dispersed within the ceramic matrix. The ceramic nanocomposite particles of the invention prevent property degradation due to carbon nanotube agglomeration.

Background for Ceramic Nanocomposite Powders Reinforced with Carbon Nanotubes and Their Fabrication Process

1. “1.

The present invention is a method of fabricating ceramic nanocomposite particles reinforced with carbon nanotubes. This process involves a homogenous distribution of carbon nanotubes within a ceramic matrix, without the carbon nanotubes agglomerating.

2. “2.

Researchers have developed techniques for fabricating ceramic composite materials with carbon nanotubes. Laurent, C. et. al., J. Eur. Ceram. Soc. 18:2005-2013 (1998), Peigney, A., et al., Ceram. Int. 26:677-685 (2000) and Siegel, R. W., et al., Scripta Mater. 44:2061-2064 (2001), developed methods for fabricating carbon nanotubes-Fe-alumina or carbon nanotubes-SiC-alumina composite materials having a weight fraction of carbon nanotubes of 2-15% using a hot pressing process or conventional sintering process.

It was hard to improve the properties of composite materials further, as they used a simple method of mixing powders. This is because a simple blend of powders to fabricate composite materials can’t eliminate the factors that negatively affect the characteristics of the materials, such as low density and high porosity due to agglomeration. The dispersibility was not taken into account during the fabrication of the composite ceramic materials.

Therefore the carbon nanotubes should be dispersed in the matrix material, and the microstructural shape will influence the final characteristics and sinterability for the ceramic nanocomposite to be manufactured. Consequently, because the improved dispersibility of carbon nanotubes results in sound-state composites powders, traditional techniques cannot produce composite powders that have excellent properties. The term “sound-state” is used here. The term “sound-state” used here refers to a state where carbon nanotubes have been homogeneously distributed not only on the surfaces but also within a ceramic matrix.

The present invention aims to provide a method of fabricating ceramic nanocomposite particles that includes a ceramic matrix with carbon nanotubes uniformly dispersed within the matrix. This prevents agglomeration.

In order for the present invention to achieve the above objective, it is provided a process for fabricating ceramic powder nanocomposite, which comprises: (a), dispersing the carbon nanotubes into a dispersion media, (b) using sonication to disperse the dispersion (b), (c) adding a salt that dissolves in water in the sonicated (b) dispersion (c), (d), sonicating (c), (e) drying the sonicated (d) and sonicated (d) (c), (c), (c) (c) (c), (b), (c), (c), (c) (c), (c), (c), (c), (c) (c), (c) (c) (c) (c), (c) (d (d (d (d) and calcinated (d (d) and (d) and (d) and calcining (d, and

In some embodiments, the dispersion medium in (a) is selected from the group consisting of water, ethanol, nitric acid solution, toluene, N,N-dimethylformamide, dichlorocarbene and thionyl chloride. In some embodiments the metal-based salts are mixed with the nanotubes in the water-soluble solution to form a ceramic matrix following the calcination. The ceramic matrix can be selected from aluminum oxides (in some embodiments), copper oxides (in others), nickel oxides (in others), zinc oxides (in other embodiments), tungsten oxides or silicon oxides.

The method described in this document is used to fabricate ceramic nanocomposite particles comprising a carbon nanotube homogeneously distributed in the matrix.

A carbon nanotube generally has a strength of the orders of 30 GPa, and an elastic modulus in the range of 1 TPa. Carbon nanotubes that can be used in the invention are those with a high aspect ratio. This is preferably between 10:1 and 1,000:1. Carbon nanotubes that can be used in the invention have a minimum purity of 95%. In one embodiment, tubular nanotubes with a diameter between 10-40 nm, and a 5?m length can be used. Tubular carbon nanotubes are useful as reinforcement in ceramic composite materials.

In order for a bundle to be separated into individual tubes of carbon nanotubes, the carbon microtubes must be dispersed within an appropriate dispersion media.” As long as the dispersion media can functionalize carbon nanotubes any type of solvent or solution can be used. The term “functionalize” is used. As used in this document, the term?functionalize’ refers to the fact that functional groups form around the perimeter of the carbon nanotubes within the dispersion media. Examples of the dispersion medium for dispersing the carbon nanotubes include, but are not limited to, water, ethanol, nitric acid solution, toluene, N,N-dimethylformamide, dichlorocarbene, thionyl chloride, etc. “Water, ethanol, and nitric solution have excellent properties due to the formation of electrostatic charge and carboxylation of the carbon nanotubes’ surface.

Sonication promotes dispersion in the dispersion media of carbon nanotubes.” Sonication usually takes place at 40-60kHz for 2-4hrs. Ultrasonic cleaning systems are available, such as the Model 08893-16 (Cole-Parmer, Vernon Hills, Ill.). a Model 08893-16 (Cole-Parmer, Vernon Hills, Ill.).

As long as metal-based salts can be transformed into ceramic materials, and reinforced with carbon nanotubes following a calcination procedure, any ceramic material can be used as a matrix material. Matrix materials usable with the present invention include, but aren’t limited to, any metal-based salts that can be formed into a matrix after calcination. Metal-based salts can include aluminum hydroxides and water-soluble copper, tin, chromium, magnesium, tungsten, or silicon salts.

After adding the metal-based water-soluble salts to the dispersion sonicated, a second ultrasound is performed.” The second sonication takes place under conditions that are similar to those of the first. The second sonication may be performed at 40-60kHz for a period of 10 hours. The surface of carbon nanotubes may be damaged if the second sonication continues for longer than 10 hours. A defect is when the graphite structure on the surface of carbon nanotubes is destroyed. “Sonication treatments are used to disperse carbon nanotubes in the dispersion media and to form chemical bonds at the molecular scale between the carbon and matrix.

Drying and Calcination are performed in an atmosphere which does not damage carbon nanotubes. For example, in a vacuum, hydrogen atmosphere, or inert gases such as nitrogen or argon. The conditions of calcination are different depending on the final ceramic matrix used. The following conditions can be used to dry and calcine ceramic nanocomposite materials reinforced with carbon nanotubes.

Gases such as water vapor, hydrogen gas and nitrogen can all be removed through drying. Stable ceramic powders are then produced by calcination. Ceramic nanocomposite reinforced with carbon nanotubes are thus fabricated.

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