The unbonded phase ultrafine pure tungsten carbide materials with nearly complete density were obtained by plasma sintering. The ultrafine microstructure with an average particle size of 200nm remained basically unchanged before and after sintering. The hardness of this material is obviously higher than that of conventional tungsten carbide-based cemented carbide, so it can be used as excellent hard material. On the other hand, fine grain size can improve the performance of hard materials. Existing conventional sintering methods require part of the liquid phase, and some WC grains are dissolved in the liquid phase. It then precipitates out on other grains, allowing the latter to grow. The larger the particle size of the original WC powder is, the greater the solubility and dissolution rate of WC in the liquid phase will be, and the bigger the growth will be during sintering. Moreover, the treatment time is too long to obtain ultra-fine (under 500nm) hard materials.

WC is the most commonly used hard material. As the melting point of WC is as high as 3048K. Usually, cemented carbide tool is produced and utilized in the way of wc-co, etc., which plays a bonding role. The addition of CO and other bonding phases not only reduces the hardness, corrosion resistance and oxidation resistance of materials, but also complicates the production process, and is likely to cause thermal stress due to the difference in thermal expansion coefficient with WC. In addition, usually when machining steel pieces, due to the presence of low melting point bonding phase co, the cuttings are easy to stick to the tool and affect the tool use effect. On the other hand, fine grain size can improve the performance of hard materials. Existing conventional sintering methods require part of the liquid phase, and some WC grains are dissolved in the liquid phase. It then precipitates out on other grains, allowing the latter to grow. The larger the particle size of the original WC powder is, the greater the solubility and dissolution rate of WC in the liquid phase will be, and the bigger the growth will be during sintering. Moreover, the treatment time is too long to obtain ultra-fine (under 500nm) hard materials.

In recent years ON 13 debut of the discharge plasma sintering technology (referred to as SiX5). By special power control device ON. OFF dc pulse voltage Inca to pressure powder test material. In addition to the sintering promotion effect caused by usual edm (discharge impact pressure and joule heating), the sintering promotion effect caused by the spark discharge phenomenon (instantaneous generation of high-temperature plasma) in the initial pulsed discharge phase is also effectively utilized.

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