Abstract We have prepared (Er1-xSmx)2Fe17Cy(x≤0.8,1.5≤y≤2.5) Compounds with a rhombo-hedral Th2Zn17- type structure by melt-spinning . These carbides are found to be stable at high temperature. The (Er1-xSmx)2Fe17Cy carbides with y = 2. 5 have unit cell volumes about 6.3% larger and Curie tewperatures about 330-360K higher than those of the 2:17 parent compounds. Room-temperature saturation magnetizations increase with increasing C content. It is found that the carbides containing Sm exhibit easy c-axis anisotropy at room temperature. The anisotropy field of (Er0.2Sm0.82Fe17C1.5 at room temperature is 8T.