LAUSR

Abstract To experimentally determine the isothermal sections of Co−Mo−Zn ternary system at 600 and 450 °C, the equilibrated alloy and diffusion couple methods were adopted by using scanning electron microscopy coupled with energy-dispersive spectrometry, X-ray diffractometry and electron probe microanalysis. Experimental results show that there are six three-phase regions on the Co−Mo−Zn isothermal section at 600 °C and nine three-phase regions on the Co−Mo−Zn isothermal section at 450 °C. No ternary compound is found in these two isothermal sections. Both the maximum solubilities of Mo in the Co−Zn compounds (γ-Co5Zn21, γ1-CoZn7, γ2-CoZn13 and β1-CoZn) and that of Zn in e-Co3Mo are no more than 1.5 at.%. The maximum solubilities of Zn in μ-Co7Mo6 are determined to be 2.1 at.% and 2.7 at.% at 600 and 450 °C, respectively. In addition, the maximum solubilities of Co in MoZn7 and MoZn22 are 0.5 at.% and 4.7 at.% at 450 °C, respectively.