Pei Bian

Polymerization of monomer-based ferrofluids.

Ferrofluids based on oleate-stabilized nanoparticulate magnetite in cyclic olefin carrier solvents were prepared. Puddles of fluids containing 20-70 wt % magnetite in 1,5-cyclooctadiene or dicyclopentadiene can be moved or positioned on surfaces or in vessels with moderate magnetic fields (inexpensive NdFeB magnets). The surfaces of puddles with concentrations >40 wt % distort in response to magnetic fields applied perpendicular to the puddle surface and exhibit pointed liquid asperities. The liquid surface topography (asperity height and number per unit area) can be controlled by the strength of the applied field. The cyclic olefin carriers can be polymerized by ring-opening metathesis, solidifying the ferrofluid samples in the shape of the magnetically distorted monomeric solvent suspensions.

Fabrication of Magnetite Nanoparticals and Drug Delivery Observation of Hydrophobe Ferrofluid by SPring-8 Synchrotron Radiation

Magnetic nanoparticles are widely used in magnetic fluid, magnetic grinding materials, magnetic controllers, magnetic sensors, biomedicine fields and so on. Recently, more and more attentions were focused upon DDS (Drug Delivery System). In this study, Magnetite nanoparticles about 8nm size were synthesized by liquid phase precipitation method. Then the nanoparticles coated with surfactant were dispersed throughout kerosene and inject the solutions into biomaterials. Using strong photon beams in SPring-8 facility, we observed the distribution state and the effect of magnetic field on the behaviour of nanoparticles in biomaterials.

Development of Ferrite Magnetic Materials with High Strength by a Low-Temperature Sintering Method

Magnetite (Fe3O4) ferrite magnetic materials have attracted attention arising by the chip coil electronic material. However, its industrial applications have been limited by the need for high temperature sintering under reduced pressure or vacuum. In order to develop the process method of low-cost and energy saving with high-strength and high magnetism of the magnet, in this paper, a new low-temperature sintering method using CO2 gas and adding a small amount of boric acid (H3BO3) is proposed. Here, the super fine magnetite powder was fabricated by decomposition from ferrous oxalate at 500 in CO2 gas. The ferrous oxalate was synthesized using iron chloride and ammonium oxalate through liquid phase precipitation. The magnetite powder compact was produced by Newton press and CIP (cold isostatic press) after adding a small amount of boric acid. In this study, the effects of the additive on the mechanical and magnetic properties of the sintered magnet were also evaluated. By characteristic evaluation of the magnet, the validity of the proposed new low-temperature sintering process and the optimal process conditions were confirmed.

Bio-medicine Coating on Surface of Magnetic Nanoparticles and Its Safety Evaluation

The composite magnetic nanoparticles of coated SiO nano film with about 8 nm size can be dispersed in various liquid media, widely known as magnetic fluids or ferrofluids with both magnetic and liquid properties. In this paper, a bio-medicine coating technology on surface of magnetic nanoparticles and the optimum fabrication condition and the magnetism of composed bio-nanoparticles are investigated. Through observation of micro-structure of the bio-nanopaticles on coating surface, and evaluation of magnetic property and safety to apply to biomaterials, we know the bio-medicine coated on surface of magnetic nanoparticles is suitable of bio-solutions into surface of biomaterials.

Evaluation of the Electromagnetic Characteristics on Ag/NiCuZn Ferrite Sintered Bodies

Recently, the surface mounting devices (SMD) have been rapidly developed for miniaturisation of electronic applications such as cellular phones, cameras, computers, etc. Low temperature sintering NiCuZn and MnCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960OC).The purpose of this study is to fabricate NiCuZn and MnCuZn ferrite sintered body with high-strength and high-frequency magnetic properties. Following is the procedure: firstly, NiCuZn and MnCuZn ferrite powder were synthesized under CO2 atmosphere at 500 OC from the mixed doxalate synthesized by liquid phase deposition method; then a small amount of boric acid [H3BO3] was added to the powder, and the NiCuZn and MnCuZn ferrite powder compact were prepared with Newton press and CIP methods; finally, NiCuZn and MnCuZn ferrite sintered body was fabricated by sintering at 900 OC under CO2 atmosphere. The effect of boric acid additives on growth of particle and sintering temperature were discussed. The high frequency magnetic properties and density as well as bending strength of the NiCuZn and MnCuZn sintered magnet with various adding of H3BO3 as well as at various sintered temperatures were evaluated by using Impedance analyzer, TMA (Thermo Mechanical Analyzer), TEM (Transmission Electronic Microscopy) and 3-point bending test. From the evaluated results, the most suitable producing conditions were determined and NiCuZn ferrite with wider scope of high frequency and high bending strength were obtained.

Magnetite nanoparticles surface coating SiO2 and magnetic properties evaluation

Magnetite nanoparticles were obtained by liquid phase precipitation method in which the pH value of [FeCl2⋅4H2O], [FeCl3⋅6H2O] and [NaOH] solution were controlled. Then the magnetite nanoparticle were scattered in water solution and put in [Na2SiO3] and [HCl], the resultant of reaction SiO2 can be coated on magnetite nanoparticles surface. The morphology and magnetite properties of the coated nanoparticles were evaluated by XRD, TEM, FTIR and VSM. The SiO2 thin film with nanometer size was coated on surface of nanoparticle, so that the magnetic value is decreased with the coating thickness increasing.

Low-Temperature Sintering and Electromagnetic Properties Evaluation of (Ni/Mn)CuZn Ferrite

Low temperature sintering (Ni/Mn)CuZn ferrite was employed at most cases due to its co-firability with Ag (below 960 °C).The purpose of this study is to fabricate (Ni/Mn)CuZn ferrite sintered body with high-strength and high-frequency magnetic properties. Following is the procedure: firstly, (Ni/Mn)CuZn ferrite powder was synthesized under CO2 atmosphere at 500 °C from the mixed doxalate synthesized by co-precipitation method; then a small amount of boric acid [H3BO3] was added to the powder, and the (Ni/Mn)CuZn ferrite powder compact was prepared with Newton press and CIP methods; finally, (Ni/Mn)CuZn ferrite sintered body was fabricated by sintering at 900 °C under CO2 atmosphere. By this method, NiCuZn and MnCuZn ferrite sintered bodies with 0.5 mass% boric acid were obtained, the strength are 430 and 530 MPa respectively. The effect of various Mn addition on NiCuZn electromagnetic properties were studied.

A New Low-Temperature Sintering Method for NiCuZn Ferrite

Low temperature sintering NiCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960°C). The purpose of this study is to fabricate NiCuZn ferrite sintered body with high-strength and high-frequency magnetic properties. Following is the procedure: firstly, NiCuZn ferrite powder was synthesized under CO2 atmosphere at 500°C from the mixed doxalate synthesized by liquid phase deposition method; then a small amount of boric acid [H3BO3] was added to the powder, and the NiCuZn ferrite powder compact was prepared with Newton press and CIP methods; finally, NiCuZn ferrite sintered body was fabricated by sintering at 900°C under CO2 atmosphere. By this method, NiCuZn ferrite sintered body with 0.5 mass% boric acid was obtained, which was additive with strength 340 MPa, high frequency applied scope below 20MHz and initial permeability 38.

Characteristic Evaluation of High Corrosion Resistant Ti/ (Pt + B2O3) Electrode with New Microstructure of Coat

In order to improve the durability of Pt coated Ti electrodes as an anode of the sulfuric acid system electrolysis, tantalum oxide (Ta2O5) additions have been used widely. However that is not enough for uses under severe conditions. In this study,boric acid (H3BO3) was added into the Pt coating during manufacturing process of Ti/Pt-coated electrodes, and the (Pt + B2O3)/Ti electrodes were obtained. The effect of H3BO3 addition on the microstructure, surface area, and lifetime of (Pt + B2O3)/Ti electrodes was also investigated in detail. Commercially available titanium plates (10 100.5mm) were employed for prepare Ti/ (Pt + B2O3) electrodes, where it was confirmed by XRD that B2O3 formed by heating the boric acid was amorphous in the temperature range of 250 to 550. The coating solution of 2 μl of H2PtCl66H2O (Pt:50 g/l) dissolved in butanol and 5~20 mass% H3BO3 mixture was spread over the etched Ti plates. After drying at 70 for 30 min, the substances were heated at 250 to 550 for 10 min. The lifetime of the electrodes was examined by a direct current of 1 A using Pt plate as the counter electrode in 1 M H2SO4 solution at 40. The end of life was determined as the time when the cell voltage changed 2 times of the beginning.