44results about How to "No surface cracks" patented technology

In the present invention, according to a method for preparing a high-permeability amorphous compressed powder core by means of high-temperature molding, wherein the variable range of effective permeability is small even at a high frequency band, it is possible to prepare an amorphous compressed powder core having a small variable range of effective permeability even at a high frequency band, an effective permeability of 75 or more, and a significantly small core loss of 300 mW / cc or less under conditions in which the frequency is 50 KHz and the induced magnetic flux is 1,000 Gauss, by coating twice, i.e. with phosphoric acid coating and polyimide-based coating as insulators between powders, and then automatic compression molding at a temperature of about 200-550̊C by using molybdenum disulphide (MoS2) or graphite powder which can be lubricated at a high temperature. Also, the present invention provides a high-permeability amorphous compressed powder core by means of economical high-temperature molding, wherein the high-permeability amorphous compressed powder core obtained by means of automatic molding at a high temperature has high molding density and no surface cracks, has good insulation properties amongst particles so as to be less dependent on frequency, and also has a small variable range of effective permeability even at a high frequency band. Therefore, the high-permeability amorphous compressed powder core can be used as a magnetic material for electric and electronic devices that are operated at a frequency band of several KHz to several tens of MHz.

The invention relates to a high-performance bonding platinum alloy fine material for packaging and a preparation method thereof, belonging to the technical field of packaging bonding materials. The weight percent of each component of the bonded platinum alloy fine material is: Ir: 0% to 60%, Ge: 0% to 5.0%, one or more of Be, Dy and Eu, and the total of Be, Dy and Eu The content is 0.03% to 0.1%, and the balance is Pt. The preparation steps include preparation of master alloy, down drawing continuous + directional solidification casting alloying, rough drawing + online annealing + fine drawing and precision rolling + online resistance heating softening treatment. The alloy has the advantages of high purification, ultra-fineness, and high refinement. It also has the advantages of high strength, good corrosion resistance, long service life, and meets the needs of extreme harsh environments. It is suitable for packaging and bonding requirements in special fields, especially It is of great significance to the development of high-end semiconductor devices to meet the application requirements of narrow chip pitch miniaturization, high reliability and high stability.

The invention discloses a preparation method of metal short fibers and a chopping device thereof. The method comprises the following steps: firstly, metal long fiber materials are forwards fed under the effect of a clamping mechanism, are fed into a through mold hole of a fixed knife mold by a guide pipe, wherein the fixed knife mold is provided with a movable knife mold fitting the fixed knife mold to cut off the metal long fiber materials, and an outlet of the through mold hole of the fixed knife mold is a cutting edge; then, the metal long fiber materials are continuously fed forwards under the effect of the clamping mechanism, and penetrate through the through mold hole of the fixed knife mold; when the metal long fiber materials extend beyond a preset length of the through mold hole, the movable knife mold moves peripherally, and a linear edge thereof goes through next to the cutting edge of the through mold hole of the fixed knife mold; and the two edges form an opposite cutting movement to finally cut off the metal long fiber materials extending outside the through mold hole so as to obtain short fibers with the needed lengths. The method has the advantages of simple process steps, convenience for operation, easy execution and lower production cost, and is suitable for large-batch industrial production.