High Performance Tungsten Carbide Ceramic Materials

Tungsten carbide ceramics are widely used in aerospace, machinery industry, electronic power, armor, chemical industry and other fields because of their excellent performance in strength, wear resistance and corrosion resistance. Among the various properties mentioned above, the hardness of tungsten carbide is still insufficient compared with the other properties. Therefore, how to improve the hardness of tungsten carbide so as to achieve a balanced performance in all aspects, so that it is more suitable for various fields.

The preparation method of high performance tungsten carbide ceramic materials includes the following steps:

(1)Tungsten carbide and micron boron carbide are proportionally weighed, mixed and poured into 1.2-1.4 times of absolute ethanol of the sum of their qualities. The suspension 1 is obtained by ultrasonic dispersion of 40-45 minutes with power of 280-300W and frequency of 34-36kHz.

(2)Yttrium oxide and nano-silica were added to suspension 1 proportionally, and then the suspension 2 was dispersed by ultrasonic wave with power of 220-240W and frequency of 28-30 kHz for 5-8 minutes.

(3)Rutile was added to the suspension 2 proportionally, and the suspension 3 was obtained by dispersing the ultrasonic wave with power of 380-420W and frequency of 25-26kHz for 25-30min.

(4)Put the suspension 3 and 14-16 times the quality of zirconia ball into the planetary ball mill tank, grind it for 10-12 hours at 400 r/min speed, and separate the suspension 3. Dry it for 4-6 hours in the blast oven at 85-95 ℃, and sieve it through 100-120 meshes to get the mixed raw materials.

(5)The high-performance tungsten carbide ceramics were obtained by sintering the mixed raw materials in graphite mould in nitrogen atmosphere with sintering pressure of 10-14 MPa, sintering temperature of 1460-1500 ℃ and sintering time of 40-50 min.

The above method takes tungsten carbide as the main body, and by incorporating rutile, cerium oxide, nano cerium oxide and other components, a high-performance tungsten carbide ceramic material having a Knoop hardness of 2650-2950 kgf· mm-2, the flexural strength is 880-935 MPa, the fracture toughness is 7.9-8.5 MPa·m1/2, and the elastic modulus is 39780-47340 MPa.

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