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The elucidation of the mechanism for steel corrosion under a coating layer has been attracting research attention. Herein, we utilized a confocal micro-X-ray fluorescence (XRF) analytical instrument to conduct non-destructive elemental analysis near the surface of a steel sheet. Using this method, elemental map images of steel sheet cross sections were obtained without sample destruction. To confirm corrosion suppression in the presence of Mg ions, we observed the corrosion behavior of hot-dip galvanized steel sheets immersed in an aqueous NaCl solution to which Mg ions were added. By using the confocal micro XRF system, the elution of the coating components and the precipitation process of the corrosion products were confirmed.

Non-destructive and non-contact analysis has been in demand on numerous occasions. Confocal micro X-ray fluorescence analysis enables depth-selective elemental analysis of solid samples in the laboratory. In this paper, we applied this technique for imaging elemental distributions in solutions. A low-carbon steel sheet was placed in artificial seawater (NaCl: 3.5 mass%), and the corrosion process in the solution was observed. A depth image of Fe Kα intensity in the NaCl solution was obtained by using this technique. The Fe Kα intensity in the solution was measured with corrosion time by sequential line analysis at a fixed lateral position. The corrosion of Fe from the steel sheet, the migration of Fe ions in solution, and their condensation near a polymer window were successfully monitored. Copyright © 2014 John Wiley & Sons, Ltd.

A confocal micro-X-ray fluorescence (XRF) method with a vacuum chamber was used for investigation of underfilm corrosion that occurs on a painted steel sheet used for automotive applications. A painted steel sheet was prepared by applying electrodeposition coating onto an electro-galvanized steel sheet with a zinc phosphate conversion coating. The spatial resolution of the confocal micro-XRF was about 10.9 ?m at an energy of 17.4 keV. The phosphorus signal from the zinc phosphate layer was able to be observed nondestructively by measuring under the vacuum condition. Each layer of the painted steel sheet was observed from the depth profile analysis of the characteristic elements of each layer. The painted steel sheet was scratched to expose the substrate surface, and then the sheet was then immersed in a NaCl solution for 10 days. The in-depth elemental map of Ti of the corroded steel sheet revealed blister-type corrosion around the scratch. The in-depth elemental maps of Zn and P suggested that the zinc phosphate layer dissolved from the scratched part into the NaCl solution.

Rare earth bonded magnets with versatility on shaping and high density, composed of isotropic Nd-Fe-B powder and thermoplastic resin (Nylon-12, PBT and PPS), were developed with warm compression molding.(1) Compounds with magnet powder volume fraction of 80vol.%, composed PBT or Nylon-12, have versatility on shaping and compressibility at relatively low pressure. Coin-shaped magnets with a thickness of 0.3mm and ring magnets with a wall-thickness of 0.4mm were moldable with these compounds at the pressure of 250MPa. The properties of these bonded magnets were as follows: pore=0vol.% in substance, density =6.2Mg/m3 and (BH)max=97.9kJ/m3 (12.3MGOe).(2) Compounds with magnet powder volume fraction of 90vol.% have higher compressibility than the compounds for compaction molding at high pressure. This is because that viscosity of resin during the molding is easy to optimize and spring-back after molding is small in warm compression molding. The properties of the magnet were as follows: density=6.7Mg/m3 and (BH)max=115kJ/m3 (14.4MGOe) at pressure of 1250MPa.In this way, warm compression molding is applicable to extensive compounds through adjusting the molding condition.

New systems for millimeter and submillimeter wave ESR have been developed in Kobe University. In the previous system the pulsed magnetic field was limited up to 17 T in the temperature range from 1.8 to 86 K. Using the new systems, we can measure in the field range up to 30 T in the temperature range from 1.8 K to 4.2 K and from 18 K to room temperature. The resolution of the magnetic field has been also improved in the new ESR system. The details of our new ESR systems are presented. In addition, the measurements of Yb2Cu2O5 using these new systems are presented.

The hot stamping process has been widely applied to the production of automotive body parts because the stamped panels with both high strength and good shape-accuracy are easily obtained. For the purpose of omitting the de-scalling treatment, the galvannealed (GA) boron steel for hot stamping was developed. When the steel is hot formed with the existence of liquid zinc, brittle fracture occurs by the infiltration of liquid zinc into the solid metal. This phenomenon is well known as Liquid Metal Embrittlement (LME). In this study hot V-bend test was carried out to estimate LME behaviour for GA boron steel in terms of suitable conditions of both heating and forming processes. First, LME disappeared with an increase of dwell time in gas furnace. In this heating condition, the dwell time that LME disappeared was 225 s. And the depth of LME crack became small as dwell time, and LME crack of 10 micrometer size was also observed in the dwell time of 210 s just before liquid zinc would be completely depleted from the Г contents index IГ based on X-ray diffraction pattern analysis for Г-phase of V-bent test specimen. In addition, in such condition, LME did not occur when a bending strain was small of 0.05 true strain. The overbend crush test for V-bent test specimen was carried out to investigate the influence of LME crack on the crash performance. Consequently it turned out that LME crack of about 10 micrometer did not have much influence on the crash performance. And this method is supposed to be very simple and valuable as a quality verification test for LME of the hot stamped parts in production.

High-energy extrusion-molded magnets, composed of isotropic Nd-Fe-B powder and Nylon-12, were developed. The mechanical properties and packing factor of the extruded products were investigated. With proper adjustment of the magnetic powder distribution, the extruded products contained 78 vol% magnetic powder and had a (BH) max of 9.9 MGOe. The shearing strength of the extruded products was 7.83 kgf/mm2, which is about 1.6 times that of compression-molded magnets with the same formulation. The porosity fraction in the extruded products was 1.1%, which is significantly less than in compression-molded magnets.

Production of resin bonded rare-earth magnets is growing rapidly. Considerable effort has been directed toward inproving the properties of the magnetic powder for the purpose of high performance resin bonded rareearth magnets. Little attention, however, has been paid to the bonding technology.In this paper, the densification behavior of compression molded resin bonded rare-earth magnets which consist of isotropic Nd-Fe-B powder, epoxy resin and lubricants was studied.The results obtained are summarized as follows:(1) The local density in the compact decreases linearly and the local pressure drops exponentially with increasing distance from the pressing punch.(2) This pressure drop is caused by the friction between the compact and the die walls.(3) Suitable lubricants improve compressibility and result in high density and a corresponding high energy product.

A new method of melt spinning using grooved and ceramic-coated chill rolls was developed. The rolls have a great effect on improving magnetic properties, which can be attributed to the achievement of a fine and uniform microstructure in the ribbons. Such rolls decrease the heat transfer coefficient at the contact surface of rolls and ribbons', and make the cooling rate of the ribbons uniform. Since the trapped atmospheric gas between the rolls and the ribbons expelled along the grooves, the occurrence of coarse grains was prevented. Using this method, Nb-added nanocomposite magnets were produced. The Nb addition had the effect of grain refinement and enhancing the magnetic properties. The maximum (BH)/sub max/ of resin bonded magnets reached as high as 117 kJ/m/sup 3/ (14.7 MGOe). Nd/sub 2/Fe/sub 14/B single-phase magnets were also produced and showed excellent properties.

Rapidly quenched (Nd,Dy)-(Fe,Co)-B alloys were formed into ribbons. Dy substitution and Co substitution enhanced coercivity and remanence, respectively. Among the investigated ribbons, (Nd/sub 0.9/Dy/sub 0.1/)/sub 9/(Fe/sub 0.9/Co/sub 0.1/)/sub bal./B/sub 5.5/ showed the best magnetic properties. Isotropic resin bonded magnets were produced from the alloys, and the bonded magnet of (Nd/sub 0.9/Dy/sub 0.1/)/sub 9/(Fe/sub 0.9/Co/sub 0.1/)/sub bal./B/sub 5.5/ showed the highest energy product: 112 kJ/m/sup 3/ (14.1 MGOe). The irreversible flux loss after exposure at 393 K was -5.1%. These excellent properties were due to fine and uniform crystalline nanocomposite structure.

A new process has been developed to produce high-energy-product bulk Pr-Fe-B magnets without the handling of any magnetic powder or powder-like ribbons. This process consists of three main steps, casting, hot-pressing and annealing, and it minimizes the oxygen contamination of magnets. A typical composition of a cast alloy is Pr 17 Fe 76.5 B 5 Cu 1.5 . Using this type of alloy, crystal alignment along the c-axis is easily induced by hot-pressing. Copper plays two important roles in this process: its addition simultaneously achieves high coercivity and excellent magnetic alignment. The magnetic properties of hot-pressed Pr 17 Fe 76.5 B 5 Cu 1.5 magnets are: B r = 12.5 kG, iH c = 10.0 kOe, and (BH) max = 36.2 MGOe. The cast alloy of this composition also has an iHc of 7.3 kOe and a (BH) max of 9.2 MGOe after annealing at 1000°C for 24 hours. The step rise in the initial magentization curve indicates a nucleation-controlled coercivity mechanism.

In spite of the need and effort for obtaining high quality single crystals in modern structural biology, biological macromolecules are still hard to crystallize. Here we propose an improved crystallization strategy using a Si-based microarrayed chip for allowing high yield of macromolecular crystals without changing conventional screening reagents and protocols. Some crystallization experiments using commercial proteins are also presented.

The hot workability of R‐Fe‐B alloys and their magnetic properties were extensively investigated. Modified hot pressing employing a ring which constrains an alloy ingot enabled hot working without cracking at high strain rates up to e = 1 × 10−1/s. Excessive discharging of the liquid R‐rich phase was controlled and the refinement of crystal grains occurred at high strain rate hot pressing. Through these effects the maximum Hci reached 18 kOe, and a (BH)max of 33.3 MGOe with a moderate Hci of 15 kOe was obtained in a composition of the Pr‐Fe‐B‐Cu system. Post‐heat treatment at 475–525 °C was effective for enhancing Hci. It was found that even in Nd‐based alloys, a (BH)max of more than 30 MGOe was achieved by hot pressing at a high strain rate, because the change in composition during pressing is minimized.

This paper describes the magnetic properties of resin-bonded magnets having the composition R(Co.672Cu.08Fe.22Zr.028)8.35. This composition is able to possess a high intrinsic coercivity(iHc) only when Sm is adopted as the rare earth element. We studied the effects of partial substitution of Sm with Pr in Sm(TM)8.35. The obtained results were as follows:1) Saturation magnetization increased and the optimum solid solution heat treatment temperature decreased as the Pr content was increased.2) Magnetic properties such as (BH)max=14.5MGOe, Br=8.1kG, iHc=10.6k0e were achieved in Sm.5Pr.5(TM)8.35 resin bonded magnet. The achieved values are comparable to those of Sm(TM)8.35 magnets.

PURPOSE: To obtain a flange-type rare-earth permanent magnet which can be used for a magnetic bearing having a large load resistance by a method wherein the respective magnetic anisotropy directions of the flange part and the cylinder part of the permanent magnet are different. CONSTITUTION: A powder magnetizing circuit composed of a cylindrical coil 1, a ferromagnetic cylinder 2 and an intermediate unit 3 is provided on the tip of a cylinder 4. Pellets are supplied into the cylinder 4 and melted at 280-300°C by a heater 5 to obtain melt 6. Then the melt 6 is intermittently fed into the powder magnetizing circuit to which a magnetic field of 20kOe is applied (wherein H denotes the direction of flux) by a screw 7 to magnetize the magnetic powder completely. Immediately after that, the melt is injected into a cavity 11 which is composed of a ferromagnetic die 8 (hatched part) and a non-magnetic die 9 and to which a magnetic field is applied by a coil 10 and then solidified to obtain an anisotropic permanent magnet 12. With this constitution, sufficient repulsion forces can be provided at the flange part and the cylindrical part of the magnet 12 which can be used for a magnetic bearing having a large load resistance. COPYRIGHT: (C)1990,JPO&Japio

Etude de la microstructure des aimants Pr−Fe−B−Cu produits par la methode moulage/pressage a chaud/recuit

A new process has been developed to produce high‐energy bulk Pr‐Fe‐B magnets directly from the melt without the handling of magnetic powder or powderlike ribbons. The process mainly consists of only three steps—casting/hot pressing/annealing—and minimizes the oxygen contamination of magnets. A typical composition of cast alloy is Pr17 Fe76.5 B5 Cu1.5 . Using this type of alloy, a magnetic alignment is easily introduced by hot pressing. Copper plays two important roles: high coercivity and excellent magnetic alignment are achieved simultaneously by the addition of copper. Magnetic properties of hot‐pressed Pr17 Fe76.5 B5 Cu1.5 magnets are as follows: Br=12.5 kG, i Hc =10.0 kOe, and (BH)max =36.2 MGOe. The cast alloy of this composition also has an i Hc of 7.4 kOe and a (BH)max of 8.8 MGOe after annealing at 1000 °C for 24 h. The steep rise in the initial magnetization curve indicates a type of nucleation‐controlled coercivity mechanism.