Domain refinement technique for very thin silicon steel sheets

在日本，电力变压器的电能损失为1.5*10^<10>kWh/年。为了降低功率损耗，有必要获得用于功率Transformer铁芯的新材料。本研究以开发新型极低损耗取向硅钢片为目的，研究了薄取向硅钢片表面开槽对磁畴细化的效果，动态磁畴观察，明确了磁畴运动与涡流损耗的关系，估算了磁畴细化样品的损耗。我们发现静磁能通过在表面开槽使磁畴宽度变窄。阐明了畴壁运动产生涡流损耗的机理。在50 Hz、1.7T条件下，32 μ m厚的取向硅钢片的损耗值为0.21W/kg，是普通取向硅钢片损耗值的1/5，是一种降低变压器电损耗的新材料。此外，还提出了新的磁畴细化机制，阐明了磁畴运动与涡流损耗的关系。

Electric energy loss at power transformers is 1.5*10^<10>kWh/year in Japan. To reduce the power loss, it is necessary to obtain a new material for the power transformer core. The purpose of this research work is to develop new grain oriented silicon steel sheets with very low loss.We did examination of effects for domain refining by grooving on the surface of the thin grain oriented silicon steel sheets, dynamic domain observation, clarifying relation between domain movement and eddy current losses, estimation of the loss of domain refined samples. We found the magneto-static energy make the domain width narrow by grooving the surface. The mechanism of generating the eddy current loss by domain wall movement were clarified. The loss value of a 32mu m thickness sample obtained by this work is extremely low as 0.21W/kg at 50Hz, 1.7T.This value is 1/5 compare with the loss of the conventional grain oriented silicon steel sheets.In conclusion, this work succeed to obtain the new material for reducing the electric power loss at the transformers. In addition, new mechanism for domain refinement are developed and the relation of domain movement and the eddy current loss were clarified.