Compound magnetic powder and magnetic powder cores, and methods for making them thereof

Abstract

The present invention provides a compound powder for making magnetic powder cores, a kind of magnetic powder core, and a process for making them. Said compound powder is a mixture composing of powder A and powder B, the content of powder A is 50-96 wt. % and the content of powder B is 4-50 wt. %, wherein powder A is at least one selected from iron powder, Fe—Si powder, Fe—Si—Al powder, Fe-based nanocrystalline powder, Fe-based amorphous powder, Fe—Ni powder and Fe—Ni—Mo powder; powder B bears different requirement characteristics from powder A and is at least one selected from iron powder, Fe—Si powder, Fe—Si—Al powder, Fe-based nanocrystalline powder, Fe-based amorphous powder, Fe—Ni powder and Fe—Ni—Mo powder. Said powder B adopts Fe-based amorphous soft magnetic powder with good insulation property as insulating agent and thus core loss of magnetic powder core decreases. The decrease of magnetic permeability of magnetic powder core resulting from a traditional insulating agent is remedied and the initial magnetic permeability of magnetic powder core is improved by taking advantage of soft magnetic properties of Fe-based amorphous powder.

1 . A method for preparing a compound powder for making magnetic powder cores, the method includes the following steps:
 a. Preparing powder A and powder B according to different requirements characteristic, respectively;   b. Screening the prepared powder A and powder B, respectively;   c. Annealing powder A and powder B according to the pre-determined parameters, respectively.   d. Uniformly mixing powder A with powder B, where the content of weight percentage of each is: powder A is 50-96 wt. % and the content of powder B is 4-50 wt. %, wherein powder A is one selected from iron powder, Fe—Si powder, Fe—Si—Al powder, Fe-based nanocrystalline powder, Fe-based amorphous powder, Fe—Ni powder and Fe—Ni—Mo powder and the selection of powder A has priority to satisfy the in requirement characteristic; powder B bears different requirement characteristic from powder A and is at least one powder selected from iron powder, Fe—Si powder, Fe—Si—Al powder, Fe-based nanocrystalline powder, Fe-based amorphous powder, Fe—Ni powder and Fe—Ni—Mo powder.   
     
     
         2 . The method for preparing a compound powder for making magnetic powder core according to  claim 1 , characterized in that, the mixing time is: 1 minute to 60 minutes. 
     
     
         3 . A method for preparing a compound powder for making low core loss magnetic powder core, characterized in that, the process includes the following steps:
 a. Preparing powder A and powder B according to different requirement characteristic, respectively wherein powder B is made to have good insulating property;   b. Screening prepared powder A and powder B, respectively;   c. Annealing powder A and powder B according to the pre-determined parameters, respectively.   d. Uniformly mixing powder A with powder B, where the content of powder A is 80-96 wt. % and the content of powder B is 4-20 wt. %, wherein powder A is one selected from iron powder, Fe—Si powder, Fe—Si—Al powder, Fe-based nanocrystalline powder, Fe-based amorphous powder, Fe—Ni powder and Fe—Ni—Mo powder and the selection of powder A has top-priority to satisfy the requirement characteristic; powder B is Fe-based amorphous soft magnetic powder with good insulating property.   
     
     
         4 . The method for preparing a compound powder for making low core loss magnetic powder core according to  claim 3 , characterized in that, the method of preparing powder B is water atomization technology.