The effects of the Cr 3 C 2 content and wheel speed on the amorphization behavior of the melt-spun SmCo 7-x (Cr 3 C 2 ) x (x=0.10-0.25) alloys were studied systematically by X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC) and magnetic measurements. The ribbon melt-spun at lower wheel speed (20 m/s) has composite structure composed of mostly SmCo 7 and a small amount of Sm 2 Co 17 R. The grain size of SmCo 7 phase decreases with the increase of Cr 3 C 2 content. With the increase of wheel speed, the XRD peaks become lower and accompanied with a broad increase in backgrounds, indicating a considerable decrease in the grain size of the SmCo 7 phase. When the wheel speed increases to 40 m/s, SmCo 7-x (Cr 3 C 2 ) x alloys can be obtained in the amorphous state for 0.15≤x≤0.25 with intrinsic coercive H ci of 0.004-0.007 T. The DSC analysis reveals that SmCo 7 phase firstly precipitates from the amorphous matrix at 650 °C, followed by the crystallization of Sm 2 Co 17 phase at 770 °C.