Study On Nanocrystalline FeCuNbSiB Alloy Powder And Magnetic Powder Cores

Soft magnetic composite materials are produced by powder metallurgy process, their special properties can't be compared by other materials. In the 21th century, soft magnetic composite materials have recently regained interest as magnetic cores for electrical converts.In this dissertation, we discussed the effect of the technologic procedure parameters of FeCuNbSiB nanocrystalline powder and magnetic powder cores. FeCuNbSiB powder was obtained by mechanical ball-milled methods and nanocrystalline powder cores were prepared in our experiment and contents of insulation addition were between 1 and 5wt%, and molding pression was between 8 t/cm2 and 20 t/cm2. The results were as follows:Compaction pressure is the basement to receive high magnetic property and good strength, and adding pressure is better for permeability and strength; but too much big pressure will bring bad effect, so it's important to consider the ability of insultant to make sure proper pressure; the best compaction pressure is 16 t/cm2.Annealing treatment is also an important technology, through annealing, magnetic powder core can get high magnetic permeability, and low core loss. It's neccessary to improve the annealing temperature when the resin is not burn down. In addition, it's also important to control annealing time to make sure the strain in the magnetic powder has fully released; the best annealing treatment process is 550℃×1h.Concerning the most important insulation procedure, making sure the mica is main insulation, the addition of mica was investigated to obtain the proper addition. The results showed that:high magnetic permeability, low core loss of samples were got when increasing mica in a certainty range; when mica content is 1.0%, the magnetic propertity is best.Magnetic properties of magnetic powder cores made with different size of powder are different. Permeability of magnetic powder core with big size powder is high, but its eddy loss is also very high. To receive good property, the size of the powder must be controlled, and proper addition is good to get down the eddy current loss so as to improve its property under high frequency.Powder partical size was slimmer, the frequency properties and DC superposition charateristics of powder cores were better,and the quality factor was higher, while the inductance was lower; different effective permeability of powder cores could be obtained with different particle sizes.