New Technology to Solve the Defects of Tungsten Carbide Ceramics

Tungsten carbide ceramics are a kind of cermet with high hardness and good wear resistance. However, under traditional technological conditions, the cutting tool made of tungsten carbide ceramics has a short service life at high temperature and is difficult to be applied to high temperature conditions.

In order to solve the above problems, the researchers have innovated a new type of tungsten carbide ceramic technology, which is mainly composed of tungsten carbide tungsten silicide silicon nitride, and the preparation steps are as follows:

(1) The tungsten carbide, tungsten silicide and silicon nitride were added to the ball mill and milled 8-10h to obtain the first mixed powder.

(2) The first mixed powder was calcined at 1200-1250°C, the calcining time was 30-50min, the calcined product was obtained.

(3) Isostatic pressing products of calcined products were obtained under 120 Mpa.

(4) The isostatic pressing products were put into the hot pressed sintering furnace and sintered in an inert gas atmosphere, 20-30Mpa and 1550-1600°C, the pre sintered products were obtained.

(5) After the pre sintered product was crushed, the presintered powder was obtained, yttrium oxide, nano tungsten powder and polythene butyral were used as the pre sintered powder. Then put into ball mill, and the billet was obtained by ball milling for 15-18h.

(6) The blank is pressed and formed under 160Mpa to obtain the plain billet.

(7) The plain billet was put into a hot pressing sintering furnace and sintered at the atmosphere of inert gas, 40-45Mpa and 2150-2180°C, tungsten carbide, tungsten silicon and nitride composite ceramics were obtained.

Tungsten carbide, silicon carbide, composite ceramics prepared by the above process have excellent fracture toughness and excellent thermal shock resistance, which is beneficial to prolong the service life of tungsten carbide products under high temperature conditions.

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