Ammonium Paratungstate Preparing ZrWMoO8 Composite Ceramic Material

The problem of thermal expansion is an unfavorable factor in many areas, which is widely existing in function and structure materials such as precision components, optical fiber, circuit boards, sensors and fuel cells. ZrWMoO₈ composite ceramic material is an ideal expand controllable material.



Studies have pointed out a method that ammonium paratungstate preparing ZrWMoO₈ composite ceramic material, the steps are as follows:
1. Weighing zirconium oxychloride, aluminum nitrate and dissolving them into 100~150mL of distilled water to prepare a solution A;
2. Dissolving ammonium paratungstate, tetra-hydrate ammonium molybdate, ammonium metavanadate into 100~150mL of distilled water, and heated with stirring to completely dissolve, then to obtain solution B;
3. Both solution A and B are slowly dropped with the same speed  into a round-bottomed flask which is containing 50mL of ethanol, then white precipitate comes into being, stirring is supposed to be continually during the addition for ensuring mixing homogenous;
4. Transferring the solution to an evaporator for evaporation after the addition was completed, and then drying, milling to get a mixed powder;
5. Placing the powder in a muffle furnace at 550~650°C calcined for 2~3 hours, and then taking out to cool down to obtain a precursor;
6. The precursor powder is placed in a mold to form cylindrical specimens;
7. The precursor sample was placed in a molybdenum crucible with stamped, and placed into another ceramic crucible with a lid, the ceramic crucible is place into the resistance furnace when its temperature heated to 940~970°C. The ceramic crucible is calcined for 2 hours, and transferred into a dryer to cool down to room temperature after taken out and cooled down for 2 minutes, then we obtain the ZrWMoO₈  composite ceramic material.