Sintering process of superfine pure WC without adhering phase

Abstract

The present invention is sintering process of superfine pure WC without adhering phase, and belongs to the field of powder metallurgy and hard material application. Superfine WC powder maintained in vacuum or inert gas atmosphere as material is densified in high strength graphite mold, set together with the mold between the upper and lower electrodes inside plasma sintering apparatus, which is then vacuumized to 5Pa, and electrically heated in the sintering temperature and pressed for sintering. The sintered sample is then taken out. The process has temperature raising speed of 180 deg.c/min, sintering temperature of 1400-1600 deg.c, and temperature maintaining period of 0-8 min. The no-adhesive phase super-pure WC material is sintered in the SPS technology process, the process is simple, low in cost and short in production period, and the obtained hard material has superior performance.

Description

technical field [0001] The invention relates to a sintering method of tungsten carbide, in particular to a sintering method of superfine pure tungsten carbide without binder phase. For powder metallurgy and hard material applications. Background technique [0002] Tungsten carbide (WC) is the most commonly used hard material. Since the melting point of WC is as high as 3048K, it is usually produced and utilized in the form of sintered cemented carbide such as WC-Co, and Co etc. play a bonding role. The addition of a binder phase such as Co not only reduces the hardness, corrosion resistance, and oxidation resistance of the material, but also complicates the production process and easily causes thermal stress due to the difference in thermal expansion coefficient with WC. In addition, when steel parts are usually processed, chips tend to stick to the tool due to the existence of the low-melting-point binder phase Co, which affects the use of the tool, and the fine grain siz...

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Problems solved by technology

[0003] Found through the retrieval of prior art document, " Microstructures of binderlesstungsten carbides sintered by spark plasma sintering process " (Seng I.Cha et al.) published on "Materials Science and Engineering A" 356 (2003) 381-389 et al., "Microstructure of tungsten carbide without binder phase sintered by SPS technology", Materials Science and Engineering A, 2003, Volume 356, pages 381-389), this paper uses SPS technology to sinter pure tungsten carbide by reducing The sintering temperature (below 1700°C) and shortening the sintering time suppressed the abnormal grain growth, but the finer the original powder particle size, the lower the sintering density, and the material with fine WC particle size has more pores, and the average particle size of WC has no Ultra-fine (below 500nm)