Ammonium Paratungstate Preparing Lanthanum Doped Tungsten Wire 2/2

3. Use pressure type spray gun to spray ammonia lanthanum acid solution to blue tungsten oxide in the form of atomizing with stirring, then dry to generate blue tungsten oxide doped with ammonia lanthanum acid;
4. Put the blue tungsten oxide into a reduction furnace, and reduced in the high purity hydrogen atmosphere to obtain lanthanum & tungsten alloy powder;
5. Wash the alloy powder with quantitative hydrochloric and hydrofluoric acid, thus to remove the excess dopant and other impurities;
6. Pressed to form tungsten strip with uniform density;
7. Pre-sintering tungsten strip at 1200~400℃ for 30~50 minutes under the protective of hydrogen to obtain the pre-sintered bars;
8. Vertical sintering the pre-sintered bars in the hydrogen atmosphere to get vertical sintered strips, and then hammering the strips to generate tungsten rods;
9. Annealing the tungsten rods;
10. Hammered again to get tungsten rods with diameter 3.7mm;
11. Use big wheel to rough drawing the tungsten rods to obtain coarse tungsten wires;
12. Oxidation annealing the coarse tungsten wires in the air, and coating with graphite, and then stretching by single-mode to eliminate work hardening and reduce the tensile strength of tungsten wires;
Note: Oxidation annealing is to eliminate the innerstress in tungsten wire doped with micro lanthanum, thus to make tungsten wire has good seismic performance.
13. Get the fine tungsten wire doping lanthanum needed.

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