Tungsten Nitride Preparation

Tungsten nitride is a kind of material more popular in tungsten chemicals, some studies show that tungsten nitride is a new catalytic material, the surface properties and catalytic properties similar to platinum, tungsten nitride catalyst application can avoid the pollution caused by industrial catalyst sulfur vulcanization, therefore it has broad application prospects. Moreover, tungsten nitride is also a ceramic material with excellent mechanical and thermal stability. For these two applications, nanoscale tungsten nitride will have a significant advantage.

It can be seen that tungsten nitride is similar to tungsten carbide, and can be used as a catalyst for the decomposition of rocket hydrazine, which can be used as a substitute for platinum metal. Perhaps tungsten carbide has wide application scope, which can be studied more. So there are not many literatures about tungsten nitride, and the manufacturing technology of tungsten nitride is also relatively limited. Here is a dry spray preparation method of tungsten nitride published by Liu Fabing and other scholars.

Using ammonium metatungstate as main raw materials, the ammonium metawolframate dissolved in distilled water, then the water solution of centrifugal spray drying in hot air 250 degrees, speed 25000rpm, the spray drying conditions of feed rate of 15ml/min under the mixed solution of copper nitrate and ammonia tungstate centrifugal spray drying to prepare precursor powders.

The powder was placed in a box furnace calcined at 600 ℃, 2 hours after desalination, dehydration to obtain W oxide powder; W oxide powder mixed with alcohol wet grinding, placed in a planetary ball mill, ball ratio 10: 1, powder and sprinkling fine quality ratio of 1: 1.5, speed 150rpm / min grinding 8 hours, then the wet grinding powder is put into the tubular electric furnace. The thickness of the material layer is 1 mm, and the temperature control accuracy is increased from 500 ℃ to 750 ℃, after heat preservation 2h, the ammonia flow rate of the whole process is 200 mL /min and the purity of ammonia is 99.9%, to prepare tungsten nitride.

The resulting WO₃ powder having a primary particle size of about 100 nm and a secondary particle size of 0.64 um was nitrided at ammonia gas at various temperatures to completely convert the powder to WN at 650 ℃ and its grain size Is 35 nm, and the secondary average particle size after agglomeration at room temperature is 6.4 um.

The results show that the tungsten nitride spray drying process is more stable than other tungsten nitride manufacturing processes, and is the most ideal tungsten nitride preparation method.

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