Effects of V sub(2)O sub(5) and ZrO sub(2) on Chipping Ratio of MnZn Ferrite Core

Cracking and chipping of MnZn Ferrites usually occur during the grinding process although proper additives such as V sub(2)O sub(5) can restrain development of cracks. To study the mechanisms, the effects of adding V sub(2)O sub(5) or ZrO sub(2) to MnZn ferrite were investigated by the rattler test. It was confirmed that adding V sub(2)O sub(5) could improve the toughness of MnZn ferrite while addition of ZrO sub(2) showed opposite result. Based on micro-structure analysis, it was found that adding V sub(2)O sub(5) increased ratio of intergranular fracture mode to the transgranular but adding ZrO sub(2) caused more transgranular cracks. Besides, V sub(2)O sub(5) addition changed its grain size distribution and resulted in some larger grains. Possible mechanisms of the toughness improvement were proposed according the above findings.