显微结构及粘接剂对NiZn磁芯浸锡爆裂的影响

Influence of microstructure and adhesive on tin solder cracking of NiZn ferrite cores

采用氧化物陶瓷工艺制备NiZn铁氧体材料,研究了工艺参数、微量元素添加对材料晶粒结构、浸(焊)锡开裂的影响。实验结果表明,合适的预烧温度、球磨时间和适当的微量元素添加可以控制材料的晶粒结构,使之具有较大而均匀的晶粒、薄的晶界、低的气孔率,同时具有高的机械强度,可以解决磁芯浸锡开裂问题。粘接磁芯用的粘接剂必须与铁氧体热膨胀系数一致才能在最后环节避免磁芯受到热冲击而开裂。

Using high purity raw material, NiZn ferrites were prepared by solid-state method. Influence of process parameter and additive on the microstructure and tin solder cracking of the ferrites were studied. The results show that proper presintering temperature, ball-milling time and additives are beneficial to obtain ferrite with proper microstructure with uniform grains, thin grain boundary, low porosity and high strength, which contribute to eliminating tin solder cracking of ferrites. The adhesive with similar thermal expansion coefficient to that of the ferrite should be used to avoid tin solder cracking resulting from heat shock during adhesive bonding of cores