Synthesis of Commercial-Scale Tungsten Carbide-Cobalt (WC/Co) Nanocomposite Using Aqueous Solutions of Tungsten (W), Cobalt (Co), and Carbon (C) Precursors

T. Danny Xiao, Xinglong Tan, Maozhong Yi, Shigao Peng, Fangcai Peng, Jiangao Yang, Yu Dai

Fujian Jinxin Tungsten Co., Ltd., Longyan City, China.
Hunan ACME Technology Co., Ltd, ACME Technology Park, Changsha, China.
Inframat Corporation, 151 Progress Drive, Manchester, CT, USA.
State Key Laboratory of Powder Metallurgy, Central South University, Changsha, China.

DOI: 10.4236/msce.2014.27001                

Abstract

This paper reports the chemical synthesis of tungsten carbide/cobalt (WC/Co) nanocomposite powders via a unique chemical processing technique, involving the using of all water soluble solution of W-, Co- and C-precursors. In the actual synthesis, large quantities of commercial-scale WC-Co nanocomposite powders are made by an unique combination of converting a molecularly mixed W-, Co-, and C-containing solutions into a complex inorganic polymeric powder precursor, conversion of the inorganic polymeric precursor powder into a W-Co-C-O containing powder intermediates using a belt furnace with temperature at about 500°C - 600°C in an inert atmosphere, followed by carburization in a rotary furnace at temperature less than 1000°C in nitrogen. Liquid phase sintering technique is used to consolidate the WC/Co nanocomposite powder into sintered bulk parts. The sintered parts have excellent hardness in excess of 93 HRA, with WC grains in the order of 200 - 300 nm, while Co phase is uniformly distributed on the grain boundaries of the WC nanoparticles. We also report the presence of cobalt Co precipitates inside tungsten carbide WC nanograins in the composites of the consolidated bulk parts. EDS is used to identify the presence of these precipitates and micro-micro-diffraction technique is employed to determine the nature of these precipitates.

Keywords

Tungsten Carbide/Cobalt Nanocomposite, Chemical Synthesis, Spray Conversion, Belt Furnace, Rotary Furnace, Water Soluble Precursors, Cobalt Nanograin Precipitates

Conflicts of Interest

The authors declare no conflicts of interest.

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