Abstract: The structure and magnetic properties of compounds Nd ₂(Co_1-xFe_x)_17-yCr_y were investigated by means of X-ray diffraction and magnetic measurements. It was found that all the compounds investigated are of the Th₂Zn17-type structu re. The substitution of Cr and Fe for Co doesnt change the crystalline structu re, but leads to an increase of the unit-cell volume. The X-ray diffraction patt erns of the magnetically aligned powder samples indicate that the easy magnetiza tiondirections (EMD) at room temperature are in the basal plane for all Nd₂(Co_1-xFe_x) _17-xCr_y compounds. With increasing content Fe and de creasing Cr content, the Curie temperature T_C increases first, reachi ng a maximum at x=0.5 and y=3.3, then decreases monotonically.

Key words: Nd₂(Co1-xFe_x) _17-yCr_y compounds, Curie temperature, crystalline structure