The as-sintered sinter skin of WC-11Co-0.71Cr3C2-0.06RE cemented carbide with WC＋βmicrostructure was analyzed by scanning electron microscope, energy dispersive X-ray spectroscope and X-ray diffractometer. RE repres...The as-sintered sinter skin of WC-11Co-0.71Cr3C2-0.06RE cemented carbide with WC＋βmicrostructure was analyzed by scanning electron microscope, energy dispersive X-ray spectroscope and X-ray diffractometer. RE represents La-, Ce-, Pr- and Nd-containing mischmetal, andβis cobalt-based binder phase. It was discovered that La, Ce, Pr and Nd migrated directionally from the alloy to the sinter skin to combine with the impurity elements S and O from the sintering atmosphere during the sintering process. As a result, main dispersed phase RE2S3 and minor RE2O2S were formed in situ on the sinter skin. The mechanisms for the stimulation of the migration activity and the directional migration of RE atoms were discussed in terms of the thermodynamics stability of Cr3C2, solubility characteristic of Cr in Co and the polarization or ionization of RE atoms.展开更多
基金Project(51074189)supported by the National Natural Science Foundation of ChinaProject(2012ZX04003–021)supported by the National Science&Technology Special Foundation of ChinaProject(Y2012–010)supported by the Nonferrous Metals Research Foundation from Hunan Nonferrous Metals Holding Group Co.,Ltd.–CSU,China
文摘The as-sintered sinter skin of WC-11Co-0.71Cr3C2-0.06RE cemented carbide with WC＋βmicrostructure was analyzed by scanning electron microscope, energy dispersive X-ray spectroscope and X-ray diffractometer. RE represents La-, Ce-, Pr- and Nd-containing mischmetal, andβis cobalt-based binder phase. It was discovered that La, Ce, Pr and Nd migrated directionally from the alloy to the sinter skin to combine with the impurity elements S and O from the sintering atmosphere during the sintering process. As a result, main dispersed phase RE2S3 and minor RE2O2S were formed in situ on the sinter skin. The mechanisms for the stimulation of the migration activity and the directional migration of RE atoms were discussed in terms of the thermodynamics stability of Cr3C2, solubility characteristic of Cr in Co and the polarization or ionization of RE atoms.
