A recent investigation [1] of the compounds Sm2(Cu,Zr,Fe,Co)17revealed optimal HA,iHc, and Bras well as an energy product of 30 MGOe in the composition Sm2Cu1.6Zr0.16Fe3.3Co12. However, this compound has a nonlinear demagnetization characteristic. We have further investigated this system by varying heat treatment and/or replacing progressively larger amounts of Co by Mn or Cr. Metallography showed the microstructures of these materials to be very complex and sensitive to heat treatment. Magnetization measurements were carried out to determine the reversible temperature coefficient &agr; as a function of annealing conditions and substitutent content. &agr; was found to vary from 0.022&percent;/C to 0.060&percent;/C over the temperature range 15 C to 150 C. The room temperature saturation magnetization of these materials ranged from 4&pgr;Ms=8.64 kG to 11.5 kG. Measurements of anisotropy field HAshowed an enhancement with the replacement of Co by Mn or Cr by as much as 25&percent; above the 92.0 kOe for the original material. This suggests that a higher coercivity and thus a more linear demagnetization curve may result from the Mn or Cr substituents.