Heater assembly

Abstract

A substrate for a heating assembly comprising a mixture of a mica material with an electrically insulating material, the substrate having a thermal coefficient of expansion that is higher than pure mica. A method of manufacturing the substrate is also disclosed.

1 . A heater assembly, comprising:
 a substrate, the substrate including particles of mica, an electrical insulator having a thermal expansion coefficient higher than pure mica, and a bind; and   a thermally-sprayed heating element mechanically adhered to a surface of the substrate.   
     
     
         2 . The heater assembly of  claim 1 , wherein the electrical insulator is aluminum nitride. 
     
     
         3 . The heater assembly of  claim 1 , wherein the electrical insulator is at least one selected from a group consisting of zirconium oxide, aluminum oxide, and magnesium oxide. 
     
     
         4 . The heater assembly of  claim 1 , wherein the electrical insulator is a silicate. 
     
     
         5 . The heater assembly of  claim 1 , wherein the electrical insulator has a thermal conductivity higher than pure mica. 
     
     
         6 . The heater assembly of  claim 5 , wherein at least one of a particle size of particles in the mixture and a volume of the binder in the mixture are such that mechanical roughening of the surface of the substrate is not required for mechanical adherence of the thermally-sprayed heating element to the surface. 
     
     
         7 . The heater assembly of  claim 1 , wherein at least one of a particle size of particles in the mixture and a volume of the binder in the mixture are such that mechanical roughening of the surface of the substrate is not required for mechanical adherence of the thermally-sprayed heating element to the surface.