A Novel Method for Direct Synthesis of WC-Co Nanocomposite Powder

作者:Zhu, M.*; Bao, X. Y.; Yang, X. P.; Gu, N. S.; Wang, H.; Zeng, M. Q.; Dai, L. Y.
来源:Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science, 2011, 42A(9): 2930-2936.
DOI:10.1007/s11661-011-0681-4

摘要

In this study, a novel method, termed dielectric-barrier-discharge-plasma (DBDP) assisted ball milling and low-temperature carburization, was used to synthesize WC-Co nanocomposite powder. X-ray diffraction, scanning/transmission electron microscopy, and differential scanning calorimetry were used to characterize the microstructure of powders. Starting from W, Co, and graphite powder mixtures, the DBDP-milled W-C-10Co powder exhibited a flakelike morphology with very fine lamellar structure. The WC-Co composite powder was synthesized at 1273 K (1000 A degrees C), which is much lower than the requisite temperature for the conventional carburizing method. The obtained WC-Co composite powder had a nanocomposite microstructure in which fine WC particles were bounded by homogenously distributed Co phase, and the WC crystals had a slablike morphology with a planar size of about 200 nm and < 100-nm thickness. The combinational effect of the milling and the plasma in the DBDP milling caused a unique fine flakelike morphology and high-density interfaces in the W-C-10Co powder mixture, which is responsible for the reduced carburization temperature and the nanocomposite structure of WC-Co powder.