STUDIES ON SINTERING OF DOPED TUNGSTEN

The outstanding engineering properties of the metal tungsten are highest melting point, high mechanical strength at elevated temperatures, lowest vapour pressure, high hardness and good thermal and electrical conductivity. These unique combinations of properties are tailor-made for certain applications. One such application is for the manufacture of lamp filaments. Tungsten lamp filaments must operate at high temperature for longer duration without significant distortion of the initial coil geometry. To meet these requirements, dopants such as Aluminium(Al), Potassium (K) and Silicon (Si) are added. In the present work, experiments were conducted to study the effect of green density on sintered ingot density for different third hold currents. It was observed that the sintered ingot density increases with increase in green density at lower third hold current but sintered ingot density decreases with increase in green density at higher third hold currents