Rod-shaped heaters

Fig. 2. Temperature fields in reaction cells of the apparatus [1], equiped with a rod-shaped heater (a) and with a complex heater (b, c)...

The most simple variant of indirect heating includes rod-shaped heaters connecting opposite current inlet details of apparatus [5], In this case the big temperature radial drop is observed in reaction cell (Fig.2a). 

The manufacturing process for fabricating rod-shaped heaters is similar to those used in planar technology, because the active heater pattern is typically printed on an alumina tape that is wound around a pre-fired alumina rod or tube. The alumina allows sintering at low 02 pressure and therefore inexpensive tungsten is the typical heater material. However, leaks and the residual porosity of the materials lead to a continuous increase in electrical resistance, caused by slow tungsten oxidization. 

---