TITLE:
Synthesis of Commercial-Scale Tungsten Carbide-Cobalt (WC/Co) Nanocomposite Using Aqueous Solutions of Tungsten (W), Cobalt (Co), and Carbon (C) Precursors
AUTHORS:
T. Danny Xiao, Xinglong Tan, Maozhong Yi, Shigao Peng, Fangcai Peng, Jiangao Yang, Yu Dai
KEYWORDS:
Tungsten Carbide/Cobalt Nanocomposite, Chemical Synthesis, Spray Conversion, Belt Furnace, Rotary Furnace, Water Soluble Precursors, Cobalt Nanograin Precipitates
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.2 No.7,
July
7,
2014
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.