Metallophobic thermally applied ceramic materials

Abstract

Metal substrates coated with ceramics and resistant to attack by molten metal.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)[0001]This application is a continuation-in-part of co-pending U.S. application Ser. No. 11 / 891,470, filed on Aug. 10, 2007 and issuing on Jul. 2, 2013 as U.S. Pat. No. 8,475,606, together with now abandoned U.S. patent application Ser. No. 11 / 891,469, filed on Aug. 10, 2007, both disclosures of which are fully incorporated by reference herein.BACKGROUND OF THE INVENTION[0002]This invention relates to metallophobic thermally applied ceramic materials, and more particularly, it relates to ceramic coatings used to improve heat transfer suitable for use in molten metals such as molten aluminum.[0003]As noted, non-metallic barrier coatings are applied to metallic substrata for the purpose of protecting the substrata from chemical reaction. Such protection depends on the continuity of the coating for protection. Discontinuities in the coating can permit the transport of chemical species or agents to the underlying substrate surface where chemical ...

AI Technical Summary

Benefits of technology

The patent describes a heater assembly for heating molten metal, which is made up of a tubular sleeve that is placed in the molten metal. This sleeve is made of metal or a metal composite material and has a coating of copper-containing material on its inside surface to improve heat transfer. The copper-containing material is able to flow and eliminate air pockets between the sleeve and the coating to ensure efficient heat transfer. The heater assembly also includes one or multiple electric heating elements placed inside the sleeve to add heat to the molten metal. This heater assembly can be used to heat a body of molten metal in a heating bay without the need for a refractory coating, and the electric heating elements are connected to a power source to allow for convenient and efficient heating.

Problems solved by technology

Discontinuities in the coating can permit the transport of chemical species or agents to the underlying substrate surface where chemical reactions may occur and result in failure of the substrate.

Such discontinuities include porosity within the coating and cracks, both pre-existing and those that develop in-service.

Such heaters are very expensive and are very inefficient in transferring heat to the melt because of the air gap between the heater and the tube.

Also, heaters such electric heaters, have very low thermal conductivity values that are characteristic of ceramic materials.

In addition, the ceramic tube is fragile and subject to cracking.

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