A heating element comprises a body provided by fibrous tubes of an electrically conductive material, a voidage between the tubes providing a path for a fluid to be heated. The material may be silicon, silicon carbide, or silicon rich-silicon nitride. The heating element is manufactured by coating a fibrous...http://www.google.com.au/patents/US4982068?utm_source=gb-gplus-sharePatent US4982068 - Fluid permeable porous electric heating element
