Abstract
Molybdenum disilicide is widely used for manufacturing high-temperature heating elements owing to its low electrical resistivity, good thermal conductivity, and ability to withstand oxidation at high temperatures. MoSi$_2$heating elements with 4-5wt% of montmorillonite type bentonite as plasticzer and a small amount of Si$_3$N$_4$, ThO$_2$, and B as additives was manufactured. Extruded rods of 3.7mmø and 6.7mmø diameter and 400mm long were fabricated using a vacuum extruder, which were then sinrered for 4-5 hrs. at the max. temperrature of 140$0^{\circ}C$. After 10 minute's oxidation treatment, the diameter of the rod is reduced. The heating elements thus prepared was stable at 1$700^{\circ}C$ and the physical properties such as specific electrical resistivity, hardness, apparent densisty, thermal expansion coefficient, and bending strength were almost identical with thoes of commercial heating elements. In this study we have tried to gain the practical knowledge of manufacturing MoSi$_2$heating elements so that it may be utilized later in a research of pilot scale and eventually be transferred to industry.
