| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of producing powder for dust core which can give the characteristics of high magnetic flux density and low iron loss to a dust core molded.SOLUTION: A method of producing powder for dust core includes a step for obtaining ferrous soft magnetic powder by atomization, a reduction heat treatment step for heat treating the ferrous soft magnetic powder in a hydrogen atmosphere of 950°C or more, a pulverization step for performing pulverization after the reduction heat treatment step, a crushing step for crushing the powder passed through the pulverization step by giving a shear force with a body of rotation, a strain relief step for performing strain relief at a temperature of 500°C or higher and less than 900°C after the crushing step, and a step for applying an insulation coating of 0.05 mass% or more and less than 0.3 mass% of the powder mass on the surface of the powder after the strain relief step. The crushing step is carried out under conditions that the product of the peripheral velocity (m/s) of the body of rotation and the crushing time (s) is 1000-22000 m. |
