Tungsten Molybdenum Alloy Crucible Preparation Method

Rare earth elements are highly active metals, which are usually difficult to be extracted from their compounds in general conditions. The electrolytic extraction requires the crucible and tungsten electrode.

Some professors suggested that combine tungsten and molybdenum, together prepare tungsten and molybdenum alloy crucible, the plan is as follows:

1. The tungsten powder and molybdenum powder are pre treated and sieved respectively. The size of tungsten powder is 0.6~20 microns after screening, and the size of molybdenum powder is 0.05~10 micron. The tungsten powder and molybdenum powder after the sieve are mixed in accordance with the mass ratio of 1~9:1~9  then ball milling for 1~5h. After that mix them for 20h at normal temperature, the mixed powder made of tungsten and molybdenum is obtained as backup.

2. According to the needs of the crucible size, form a mixed powder of tungsten and molybdenum mass or volume that crucible required. Manufacturing cold isostatic pressing mould with molding cavity that is equal volume as mixed powder of tungsten and molybdenum. The molding cavity of powder feeder for the tungsten powder mixture to free fall into the cold isostatic pressing mould. The cold isostatic pressure process conditions are as follows: under 150~200MPa, the pressure maintaining is 5~10min; the powder blank is obtained by processing, and the spare part is prepared.

3. Remove the mold, take out the blank of the powder, process it with a car size machine, and as backup.

4. Put the powder into the furnace, Heating up with 30~40°C /min heating speed rate to 2150~2200°C, after heat preservation at the temperature for 8~9h, natural cooling to room temperature with the furnace, take out the green compact and as backup.

5. Use hot isostatic pressure treatment on the green compact after surface treatment. Tungsten alloy crucible was obtained. The hot isostatic pressing process as followed: Prefiring 30min at 800~1000°C, then rising to 1450~1500°C, maintaining the pressure and temperature under 180~200MPa, 1~3h.

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