Preparation of Titanium Carbide Covered with Tungsten Nanosize Composite Powder from Ammonium Paratungstate 1/2

Method of mechanical-alloying is commonly used in preparation of W-TiC alloy at present, which is using high energy grinder and ball grinder to achieve solid state alloying. However, because of the abrasion of grinding ball and ball milling tank, it is easy to introduce a large number of impurities, thereby causing the minor change of components. At the same time, the process of ball grounding will introduce large numbers of mechanical energy which make the powder stands in high energy activation state, accelerate the growth of grain in the sintering process; and due to the high internal stress, crackles will come into being in the process of briquette sintering which seriously affect the properties of W-TiC alloy. So it is urgent to find a new method for preparing composite powder of tungsten without crackles at the grain boundary, and material will not failure because of the stress concentration.

A new method for preparing W-TiC powder was proposed in this paper, which is preparing titanium carbide covered with tungsten nanosize composite powder by using ammonium paratungstate (APT) as raw material. Changing the state of TiC on the tungsten surface, not only can make the TiC uniform distribution and avoid agglomeration, overcome the problem in Mechanical-alloying method, but also can reduce impurities and controlling the composition of TiC at the same time.



Reaction principle: oxalic acid and APT reacting at a certain temperature and other conditions, crystallization for getting precursor powder of W-TiC. After adding APT into oxalic acid, the react between them will not occurred immediately which makes tungsten has enough time to nucleation on the surface of TiC powder, so structure that TiC covered with tungsten came into being. And then, tungsten nucleation in the home position to obtain titanium carbide covered with tungsten nanosize composite powder in the process.

Equipments: ultrasonic dispersing device, stirring device and drying device, tube oven for sintering
Reactants and reagents: oxalic acid, titanium carbide powder (TiC), ammonium paratungstate powder (APT)

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