Sintering behavior of Fe-Si composite powder by DPR technique

The reaction mechanism of silicon and iron composite powders was clarified during the fabrication of high silicon iron sheet with the Si-content of 6.Swt% by Direct Powder Rolling (DPR) technique. The changes of phase composition and structure evolvement were mainly studied. It is found that a local graded structure, Fe-Fe(Si)-Fe3Si(Si)-Si, forms when sintering at 950-1000 degrees C, which plays an important role in the DPR process. Fe3Si(Si) phase keeps higher content of Si, and Fe(Si) phase remains the state with much lower Si-content, thus provides good mechanical proprieties of rolling and cutting. Then, the subsequent sintering at about 1200 degrees C improves the density and makes the distribution of Si homogeneous in the final high silicon iron sheets.