Pyrolytic boron nitride radiation heater

摘要

A pyrolytic boron nitride radiation heating unit (10) including a dielectric base of boron nitride (12), a heating element of pyrolytic graphite (14) superimposed on the dielectric base, a first outer coating (16) surrounding said heating element composed of pyrolytic boron nitride and a second outer coating (18) surrounding said first outer coating (16) and having an emmissivity above at least about 0.9 at a wave length of 1.55 microns. The second outer coating is preferably selected from the group consisting of silicon carbide and boron carbide.