Abstract: Si-doped Nd-Fe-B-alloys (Nd₁₅Fe_77-xSi_xB₈, x= 4, 8, 16, 18 at% ) were prepared in a gra-phite furnace. X-ray diffraction and scanning electron micrographs of the products showedthat besides Nd₂Fe₁₄ B there were some Nd-rich phases when silicon had doped in at 8 at%.The Curie temperature(T_c) was increased from 310℃ to 350℃ by do ping with 8--16at% silicon. When Si content was greater than 16 at%, a new phase was formed and theTc of the alloy markedly decreased. The density of the alloy slightly deereases with inc-rease of Si when Si content is over 4 at%. The hardness of the alloy has a maximum va-lue at about 8 at% of Si.

Key words: Nd-Fe-B permanent magnet mattrial, Iron base RE permanet magnet, mater al, Alloy