Research On Processing Of The Tungsten Wire For Halogen Lamp

The systematic research work was dong in this paper on the processing of tungsten wires for halogen lamp based on the the quality problems of the wires made in HL company by comparisons of the properties differences between wires made in HL and foreign companies, The processing technology was optimized, so that the quality of the wires made in HL reaches the level of the products made in developed countries.The solid-liquid mixing way has an advantage over the spraying mixing, which can raise the dopant content in the TBO and make the dopant distribution uniformity. In the process of the solid-liquid mixed, PH of the dopant solution was the key factor which controls the precipitation of the colloid. The suitable level of the PH value is about 3.3, which makes operation easy and precipitation of the colloid slow.Using BD powder technique prepared the bars with different size particles tungsten powder which can improved the distribution of particle size of tungsten powder and dopant uniformality and the sintering ability of the powder to provide the high quality materials for following processing.The temperature gradient of the bars should keep in small range in sintering. It is easy to makes the temperature field uniform by use of small size bars.It is detected by the comparisons that annealing has an important effect on tungsten wire property so that the extent and rate of the re-crystallization should be controlled carefully. The sag value of the wires after final annealing is enough low when the total reduction ratio is at about 70% for 4-6 grains in cross section of the wires after finished products annealing.