Composite materials and devices comprising single crystal silicon carbide heated by electromagnetic radiation

Abstract

A composite material that increases in temperature upon exposure to electromagnetic radiation comprising single crystal silicon carbide whiskers and fibrils in a matrix material. Also, heat-generating objects comprising the composite material, and a method of generating heat.

Description

FIELD OF THE INVENTION [0001] The invention relates to composite materials that quickly and efficiently increase temperature by absorption of electromagnetic radiation. The invention also relates to devices comprising the composite materials, and to a method of heating using these devices. BACKGROUND OF THE INVENTION [0002] Many materials are known to not absorb microwave energy or other electromagnetic radiation. Such materials may be reflective or transparent to the electromagnetic radiation without being affected thereby. Therefore, these materials do not heat when exposed to microwave or radiowave fields. [0003] Many materials are known to absorb electromagnetic radiation and therefore will heat. Heating with microwave energy is but one example of this phenomenon, and many compositions that heat upon absorption of microwave energy are known. For example, water, fats, and certain food products absorb microwave energy and are heated thereby. Similarly, inorganic compounds such as ...

AI Technical Summary

Benefits of technology

[0096] Various techniques can be utilized to improve field uniformity. Techniques include: (1) using multiple magnetrons to inject microwave radiation into the chamber at different locations, (2) waveguides and wave-splitting devices to control microwave directionality, (3) metal reflectors, fans, and “stirrers” to disperse the microwave radiation, and (4) turntables or other devices to move the specimen in the field, thereby distributing the flux over the specimen.

[0097] Use of these techniques generally improves the uniformity of heating rates. However, the oven used in the experiments was a single magnetron system, and therefore had distinct

Problems solved by technology

However, not every form of such materials can be used in this way.

However, metal is highly conductive, and this high conductivity can lead to arcing or sparking.

For example, a large mass of solid metal typically cannot be placed in a microwave oven without causing damage from arcing and sparks caused thereby.

However, these systems typically have slow heating rates, thereby negating the benefits associated with microwave heating.

It is known that exposing silicon carbide, ceramic fibers, and microwave absorptive materials to microwave energy may lead to undesirable arcing and sparking.

However, if the object is not autoclaved, the heating rate is unacceptably slow.

There exist limitations on the use of silicon carbide in heat-generating objects.

The heating efficiency of even the most absorptive forms of silicon carbide typically is low.

Indeed, the heating efficiency of typical silicon carbide particulate is so low that such particulate is used to increase the strength and cut-resistance of microwave-heatable food contain

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