This work focuses on a search for magnets that can be used at elevated temperature. We have studied the effect of ZrB2 addition on the magnetic properties and stability of nanocrystalline 1:7 type Sm(Co,Ti,Zr) magnets up to 500 degreesC. Amorphous ball milled powder was annealed to develop the TbCu7 type structure. The room temperature coercivity of SmCo6.5(ZrB2)(0.033)Ti-0.4 is 2.1 T. The microstructure is stable at 400 degreesC, where the coercivity is 0.5 T. (C) 2003 American Institute of Physics.