The performance exploration and decomposition of metal powder
March 30, 2012Because the exist of distributing air spaces, characteristics of low permeability and constant magnetic permeability, the metal magnetic particles have been widely used in the field of power electronics and electronic information. With the development of the electronics industry, the requirements for miniaturization of electronic products also will be improved. So does the performance of metal magnetic particles which means that the new magnetic particles must have a high saturation magnetic flux density, low-high frequency loss and a good performance stability (including temperature stability, the stability of the different DC magnetic bias field permeability and permeability stability under different frequency). While in the use process, it produces low noise with low prices. Iron silicon boron powder alloy is a common iron-based amorphous alloy with high resistance and high saturation flux density with extremely low iron loss and low-cost advantages. The strip is easy to become brittle after annealing. It is an ideal material for magnetic particles preparation.
In the powder metallurgy process, the most important point for study amorphous material mechanical crushes performance is on the magnetic properties of new powder cores with conventional powder cores (including metal powder core temperature stability, the effective permeability versus frequency, DC superimposed field changes and the Q value at high frequencies, loss, etc.) of the difference. After pretreatment, iron-based amorphous ribbons prepared using mechanical milling legal system as amorphous powder, and at the same time be corrected airflow broken powder morphology after sieving and particle size ratio to obtain powder.
Aamorphous powder cores process is follows: powder passivation, insulation coating, molding, and curing. The metal powder in the phosphating solution passivation insulating material and the adhesive coated handle, and then joined to the powder made of ring samples in the four-post hydraulic press with pressure cold pressing. Finally the curing in air is needed.
Respectively, the powder morphology of the composite crushing prepared through ball milling and ball milling airflow. Strip directly ball crushing, powder flaky, there are a large number of sharp corners, large particles of the powder, the powder and class of a long strip of triangles powder and small particles, compared with class square. Relatively smooth powder prepared by milling airflow composite broken grain boundaries, reduce the powder of long and sharp phenomenon, the majority of powder close to the wafer-shaped. This strip broke he preparation of powder characteristics. Strip mechanical crushing milling rely mainly on the strip to break derived, which determines its sharp corners too much powder, and this topography is not conducive to the insulating coating of powder. Experiment that airflow broken law may be amended to the powder morphology, is one of effective ways to reduce the cusp morphology of the metal powder.
DC superposition is an important parameter to measure the dynamic characteristics of the nickel powder cores. In some circuits, alternating magnetic field and dc magnetic field, while the role of powder cores, powder cores in this condition not only to have good electrical and magnetic properties, but also has good DC superposition characteristic, that is superimposed on a DC bias source the effective permeability of powder cores attenuation changes as small as possible. When DC superimposed magnetic field value 100Oe, the effective permeability of the amorphous powder core attenuation changes in value of 34. It is suitable for bigger current inductance device.
Source:http://www.mhcmp.com
Posted by tracy ma. Posted In : metal powder