Ze Kun Feng

Influence of Zinc-Zirconium Substitution on Magnetic Properties of Ba(ZnZr)xFe12-2xO19 Hexaferrite Prepared by the Molten Salt Method

M-type hexaferrites Ba(ZnZr)xFe12-2xO19 (x=0, 0.5, 1.0, 1.5) powders, have been synthesized by molten salt method, where x varies from 0 to 1.5 in steps of 0.5. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer(VSM) were used to analyze the structures and magnetic properties. The results showed that, the magnetoplumbite structures for all samples calcining at 1100°C have been formed. The magnetic hysteresis loop measurements of the hexagonal ferrites powders showed that the saturation magnetization (Ms), the remanent magnetization (Mr), and the coercitivity (Hc) of ferrites depend strongly on the chemical compositions of materials. The data showed that the max Hc was obtained when substitution of x=1.0 (Hc=63.9 Oe), while the best Ms was obtained when substitution of x=0.5 (Ms=54.02 emu/g). Zn and Zr substitutions greatly modified the magnetic properties of BaM hexaferrite.

Effect of Annealing Temperature on the Soft Magnetic Behavior of Sendust Powder Core

The variation of soft magnetic properties of Sendust powder cores as a function of annealing temperature has been investigated. Toroid-shaped Sendust powder cores were prepared from Fe-Si-Al powder by machine pulverizing and subsequent cold pressing using inorganic insulating layer and organic binders, respectively. The influence of different compaction pressures and various annealing temperature on effective permeability and quality factor was investigated. Sendust powder cores using inorganic salt as insulating layer exhibit high effective permeability ( μe>110) up to 1 MHz, showing excellent frequency stable characteristics and high quality factor (Q>80) at 50 kHz. The optimized annealing temperature is 953K.

Influence of Sr2+ Doping Quantity on Microstructure and Magnetic Performance of Z Type Hexagonal Ferrite

Co2Z type planar hexaferrite doping of Sr2+ 2CoO∙3Ba1-xSrxO∙10.8Fe2O3 is made with common production process of cermet. The paper studied the influence of Sr2+ doping quantity on microstructure and magnetic performance of Co2Z type planar hexaferrite. The result indicates that when the doping quantity x=0.4, the magnetic performance in ultrahigh frequency will get improved, the initial permeability can grow to 14, and the cut-off frequency will also relatively increase to 2.45GHz.

An Interface from LabVIEW to the Knock Sensor Testing System

This paper proposes how to use a domestic data acquisition card to develop a car knock sensor testing and analysis system, which is based on the U.S. NI LabVIEW. The content of the testing section is to design a driver based on the dynamic link library, aimed at making a communication between LabVIEW and the data acquisition card. This system can realize real-time acquisition for the knock sensor output signal, and the testing interface is simple and practical.

FeSiAl Powder Core Coated by Ba-B-P-O System Insulating Layer

Sendust soft magnetic composites coated by a thin Ba-B-P-O system insulating layer were produced; SEM spectroscopy and Energy dispersive X-ray analysis spectroscopy confirmed that thin layers of Ba-B-P-O system covered the alloy powders. The influence of various compaction pressures on composites permeability, DC properties and total loss was investigated. The Fe-Si-Al magnetic powder core with compaction pressure of 1932MPa, annealing temperature of 953K with a permeability of 94, a total loss of 108 mW/cm3.

Influence of Microwave Calcination on Microstructure and Magnetic Properties of Sr-Hexagonal Ferrite

The improvement of the microstructure of Sr-hexagonal ferrite and their magnetic properties by microwave calcined method was studied, the aim of the study was to obtain a fine grained microstructure in calcined stage. There was tendency to induce a large anisotropic during grain growth, microwave calcination method can succeed in obtaining homogeneous grain growth ,and help to reduce the calcination temperature and shorten the calcination time. The ferrites with saturation magnetization, remanent magnetization and intrinsic coercivity of 70.322emu/g, 36.182emu/g, 3343.1Oe, respectively, obtained in samples calcined at 1140°C for 30 min.

Electromagnetic Noise Suppression Characteristics of FeCoBM-Al2O3 Amorphous Soft Magnetic Films

The electromagnetic noise suppression characteristics of a series of FeCoBM -Al2O3 amorphous soft magnetic films were reported in the frequency range from 0.5GHz to 6 GHz. Effect of dopants on the reflection coefficient (S11), transmission coefficient (S21) and power loss (PLOSS/PIN) of as-deposited FeCoBM(M=Nb, Zr, Hf, Ta, Mo, Ti)-Al2O3 films were studied. The (Fe40Co40B20)89Mo8–(Al2O3)3 film had the highest power loss with the value of 0.85 at 6GHz. The transmission properties of the FeCoBNi-Al2O3 also studied in the paper. The power loss of the (Fe40Co40B20)68.36Ni28.64–(Al2O3)3 film was more than 0.6 from 3.0-6.0GHz, which had the best electromagnetic noise suppression characteristics. These results show that the presented films possesses potential in noise suppressor applied in electronic devices .

Micro-Structure and Magnetic Properties of Hexagonal M-Type Ferrite Thick Films Prepared by Tape Casting

The M-type hexagonal ferrite thick films are prepared by tape casting . The morphology is investigated by scanning electron microscope (SEM), the phase composition is characterized by X-ray diffraction (XRD) and the magnetic properties are characterized by vibrating sample magnetometer (VSM). The result shows that thick film by tape casting has high remanence as 26.607emu/g, high magnetization as 55.236emu/g, high coercivity as 2323.8Oe, and high squareness ratio and a good morphology which is suitable for small and light-weight microwave and millimeter-wave devices .

The DC-Bias-Superposition Characteristics of Low Sinter Temperature NiCuZn Ferrite

The DC-bias superposition characteristics of NiCuZn ferrite with different amount of Bi2O3 have been investigated. The microstructure depends much on the amount of Bi2O3. The DC-bias-superposition characteristics have great relationship with the microstructure. The permeability of materials composed of tiny grains decreases more slowly with the increase of DC-bias superposition due to the absence of the domain walls in the grain. The nonmagnetic phase in the grain boundary can reduce the actual DC-bias superposition in the grains when the sample was subject to DC-bias superposition. In short, a microstructure with relatively small average grain size and thick nonmagnetic phase in the grain boundary, which is favorable for obtaining better DC-bias superposition characteristics.

Study on Preparation and the Noise Suppression Effect of Co2Z Ferrite Films

The Co2Z ferrites noise suppression sheet was prepared by tape casting. Its microstructural characterization was performed by electron microscopy and noise suppression effect was measured by a microstrip line method. Results indicate that as the sinter temperature increases, the imaginary permeability increases leading to the enhancement of the suppression capability, and the thickness of noise suppression sheets also contribute to the noise suppression capability.