Mechanical properties of WC–WB–W2B composites prepared by reaction sintering of B4C–W–WC powders

Synthesis of W<SUB>2</SUB>C by Reactive Hot Pressing and Its Mechanical Properties

“…2,4) The powder mixtures were consolidated in a graphite die with an inner diameter of 20 mm and outer diameter of 50 mm at 1600 to 1900 C using a resistance-heated hotpressing system (the Spark-Plasma Sintering Machine; Sumitomo Coal Mining, SPS-2080) at a heating rate of 50 C min À1 , an applied pressure of 50 MPa, and a holding time at the sintering temperature of 20 min. This hot-pressing system enables rapid heating and cooling because an electrically conductive sample and graphite die wound with graphite felt for thermal insulation are heated by passing a current through them directly via water-cooled electrodes that are used for applying pressure simultaneously.…”

“…Since the Co binder phase lowers the hardness, recent efforts to obtain harder materials have attempted the use of hot pressing to consolidate WC-Co with low amounts of Co 1) and WC with no metallic binder. [2][3][4] In such cases, tungsten hemicarbide (W 2 C) is usually produced during sintering. In addition to these processes, W 2 C is formed in thermally sprayed coatings of WC-Co 5,6) and WC 7) which are used to create wear-resistant hard surfaces on metals.…”

Microstructure and Mechanical Properties of W-C-B Ceramics Containing VC

“…The sintering procedure and characterization methods for sintered bodies were similar to those described previously. 5,7) The powder mixtures were consolidated at 1600 to 1800 C using a resistance-heated hot pressing system (SPS-2080, the Spark-Plasma Sintering Machine; Sumitomo Coal Mining) at a heating rate of…”

“…Both W 2 C and W 2 B were also produced in the B 4 C þ 5W þ 80WC powder mixture without VC, due to the slight W excess in the starting WC powder. 7) In this study, assuming that the starting WC powder contains the impurities Fe, Mo, and V as the carbides Fe 3 C, Mo 2 C, and V 8 C 7 , respectively, the molar ratio W/C for C and W to combine is 1.003. The experimental results indicate that this value is slightly higher than that for the stable WC phase.…”

“…This ceramic was still more sinterable than WC, and WC grains grew easily during sintering. 7) However, the grain growth reduced hardness considerably. As a result, the appropriate sintering temperature range for obtaining a fine-grain body was very narrow.…”