Abstract
Effects of Co addition on some properties, particularly low-temperature ductility of doped tungsten wire have been studied.
In particular, wires produced by additions of 0.01-0.06 weight % of Co together with common doping agents, Al2O3, SiO2 and K20 have shown a remarkably improved ductility before recrystallization. Increasing amounts of Co were effective in significantly increasing the maximum elongation. These wires at 0.39 mm diameter have shown the maximum elongation of 12-26% at room temperature after annealing, and the content of gaseous impurities in these wires have been effectively lowered.
These wires containing 0.01-0.03% Co are not only remarkably ductile before recrystallization but have also superior in qualities to those of ordinary doped products after recrystallization, for example excellent in high temperature sag resistances essential to lamps and tubes as well as in ductility.
