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Volume 43, Issue 1
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[in Japanese]1996 Volume 43 Issue 1 Pages 4
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (65K) -
Hiroshi Yamamoto1996 Volume 43 Issue 1 Pages 5-12
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThese experiments were carried out to investigate the effect of addition of various rare-earth oxides on the magnetic and physical properties of anisotropic or isotropic M-type (M=Ca, Sr, Pb, Ba) ferrites, and to make clear the effect of the use of a new manufacturing method and the additives on the properties of anisotropic W-type (W=Sr, Ba, Pb) ferrites.
In M-type ferrites, it was found the rare-earth oxide addition to these compounds (stoichiometric composition) was very useful in stabilizing the magnetoplumbite structure, and that these compound had excellent properties as a permanent magnet.
In M2+Zn2-W-type ferrites, a new valuable manufacturing method which is characterized by the addition of M2+O(PbO, SrO, BaO) after semisintering treatment without atmosphere control was established. It was found that this process was very useful in stabilizing the W-type hexagonal structure, and in improving the magnetic properties of these compounds. It cleared that the effective additives for the W-type ferrites are CaO, SiO2, Na2O, La2O3, MgO, Al2O3.View full abstractDownload PDF (560K) -
The Second ReportHiroshi Yamamoto, Rei Takeuchi, Haruhito Kumehara, Hiroaki Nishio1996 Volume 43 Issue 1 Pages 13-18
Published: January 15, 1996
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSThis experiment was carried out to investigate the new process of the preparation of fine particles of SrO⋅6Fe2O3 with single phase by controlling the chemical coprecipitation(a solution containing Fe3+ and Sr2+ in the ratio 10.0-12.0) and succeeding heat treatment. The new process is performed with successive as follows ; coprecipitation→boiling→drying→heat treatment. The conventional process was characterized by the washing after the coprecipitation. The conditions determined as optimum for preparing the fine powders with best values of σs= 90.5 × 10-6 Wb⋅m/kg, HcJ=350.1kA/m, average anisotropy field HAavc=915.1 kA/m and Tc= 464°C are as follows: solution composition ; Fe3+/Sr2+=10.5 ; pH=13.0 ; heat treatment ; 1000°C for 2hs in air.View full abstractDownload PDF (2152K) -
Hitoshi Taguchi, Fumihiko Hirata, Taku Takeishi1996 Volume 43 Issue 1 Pages 19-24
Published: January 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSToday, Sr-ferrite and Ba-ferrite with hexagonal structure are widely used as permanent magnets. However, Ba-ferrite is considered to be unsuitable for high performance magnets compared with Srferrite because of its lower K1 value. In this study, submicron-sized Ba-ferrite powders were prepared to achieve higher corecivity. On the other hand, addition of SiO2 and CaCO3 (or CaO) is usually carried out to get high density and inhibit grain-growth during sintering. Without difficulty, it is predicted that Sr and Ba can be substituted for Ca, because they have similar characters. Therefore, in this study, addition of alkaline-earth elements and silica was investigated systematically. As a result, by addition of Si02-SrCO3 in Ba-ferrite, high performance Ba-ferrite magnets (Br=4.3kG, HcJ=3.6kOe) were obtained. At the same time, we discovered that they have equal shrinkage ratio in a-axis and c-axis. These unique results were due to the inhibition of grain-growth along a-axis. Furthermore, Ba segregation was found at grain boundaries besides Si and Sr by TEM-EDS analysis.View full abstractDownload PDF (5553K) -
Nobuhiro Matsushita, Kenji Noma, Shigeki Nakagawa, Masahiko Naoe1996 Volume 43 Issue 1 Pages 25-30
Published: January 15, 1996
Released on J-STAGE: July 12, 2010
JOURNAL FREE ACCESSBa ferrite films were deposited epitaxially on ZnO underlayer from targets with composition of BaO.6.5Fe2O3 using the facing targets sputtering apparatus. The gas mixture of Ar and Xe at 0.18 Pa and O2 at 0.02 Pa was used as the sputtering gas and the dependences of crystallographic and magnetic characteristics on the partial Xe pressure Pxe (0.0-0.18 Pa) were investigated. Films deposited at various Px5 and at substrate temperature of 600°C were composed of BaM ferrite and spinel crystallites, and the minimum centerline average roughness Ra of 8.9 nm was obtained at Pxe of 0.10 Pa and then the saturation magnetization 4πMs, of 5.1 kG and perpendicular anisotropy constant Ku1 of 4.23 × 105 J⋅m-3 were larger than those of bulk BaM ferrite of 4.8 kG and 3.30 × 105 J⋅m-3, respectively. C-axis orientation was observed even for the film deposited at low Ts of 475°C and 4πMs, perpendicular and in-plane coercivity, Hc⊥and Hc//, were 4.7 kG, 2.38 and 0.19 kOe, respectively.View full abstractDownload PDF (1546K) -
Takashi Kojima, Naoyoshi Sato, Tamotsu Minakawa, Takeshi Nomura1996 Volume 43 Issue 1 Pages 31-35
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe effect of chemical composition and firing conditions on the core loss characteristics of MnZn ferrite has been studied with special reference to the factors of core loss. It was found that hysteresis and eddy current losses comprise most of the core loss for MnZn ferrite used at 100kHz. Especially, the eddy current loss remarkably increased with increasing the frequency in comparison with hysteresis loss. On the basis of the fact that the eddy current loss bears a linear relationship to the electrical resistivity, an experimented addition of SnO2 to MnZn ferrite has been tried to improve the electrical resistivity. As a result, MnZn ferrite with low power loss has been successfully developed.View full abstractDownload PDF (1200K) -
Nobuyuki Hiratsuka, Yoshihiko Minamiyama, Koichi Kakizaki1996 Volume 43 Issue 1 Pages 36-40
Published: January 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSAcicular manganese zinc ferrite particles were prepared and then a sintered manganese zinc ferrite with well crystal-orientation was experimentally fabricated by using the acicular particles.
As the starting materials of the acicular manganese zinc ferrite particles, the acicular α -FeOOH, Mn(C5H7O2)3 and Zn(C5H7O2)2 were used and the mixture of these materials were sintered at 900°C for 4 hours in a nitrogen atmosphere. The highest values obtained by measurement for the sintered particles were saturation magnetization of 68.8 emu/g (0.458 Wb/m2 ), coercivity of 81 Oe (6.5 kA/m), the length of the long axis of 2μm and aspect ratio of 15 respectively. As a result of chemical etching of the acicular particle, it has become apparent that several crystallites are linearly aligned in a particle.
The acicular manganese zinc ferrite particles were pressed and formed to a shape under the magnatic field of 12 kOe (960 kA/m) by wet method, and then sintered at 1250°C in air. The sintered manganese zinc ferrite strongly exhibited a uniaxial crystal-orientation similar to that of the manganese zinc ferrite single crystal.View full abstractDownload PDF (2177K) -
Nobuyuki Hiratsuka, Takeshi Miyamura, Koichi Kakizaki1996 Volume 43 Issue 1 Pages 41-45
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSMnl.xZnxFe2O4 (0≤X≤1) films were prepared by using a dual source evaporation apparatus added with an r.f.generator of 13.56MHz. When as-deposited films were annealed in a reduced atmosphere at 900°C for 5 hours, spinel-type ferrite films with single phase were formed. The films were crystal-oriented to <110> direction of the spinel structure. Mn0.7Zn0.3Fe2O4 film had the value of saturation magnetization of 485 emu/cc (0.61 Wb/m2), coercive force of 30 Oe (2.4 kA/m) and initial permeability of 550 respectively. The μ-T curve of the Mn0.7Zn0.3Fe2O4 film was appreciably different from that of the bulk Mn-Zn ferrite, because it was a solid solution composed of Mn-Zn ferrite and magnetite.View full abstractDownload PDF (270K) -
Kenji Noma, Nobuhiro Matsushita, Shigeki Nakagawa, Masahiko Naoe1996 Volume 43 Issue 1 Pages 46-51
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSCo-Zn ferrite films were expected for high density magnetic recording media and magnetic thin film devices because of its large magnetocrystalline anisotropy energy and high coercivity. Facing Targets Sputtering (FTS) method was used to deposit Co-Zn ferrite films and the films composed of well (111) oriented crystallites were attained at the substrate temperature T2 below 100°C by using sintered targets with the composition of Co0.51Zn0.45Fe2.04Oy The maximum value of saturation magnetization 4πMs of 4.8 kG was attained at Ts of 250°C and the in-plane and perpendicular coercivities, Hc// and Hc⊥ were around 1.8 kOe, respectively. It was also found that the preferred orientation of Co-Zn ferrite crystallites were strongly dependent on Ts.View full abstractDownload PDF (1392K) -
Haruki Kurokawa, Tomoaki Urai1996 Volume 43 Issue 1 Pages 52-58
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe crystallographical and morphological properties of goethite particles in the course of oxidation in the strong alkaline solution was studied from X-ray diffraction analysis under the systematically controlled synthesizing conditions. The crystallite size ratio, D010D110, was changed by excess alkali content and oxidation conditions. The particle morphology of goethite depends on the relative growth rates of each faces of goethite crystals. From the SEM observation, the vertical and horizontal axes of goethite are proposed to be (110) and the lateral growth is assumed to be occurred along (110) easily because of the topotaxy between Fe(OH)2 and goethite. It is concluded that the crystallite size ratio depends on the development of (110) face during crystal growth, which in turn, is related to the ferrous complex (FeOH+) content.View full abstractDownload PDF (392K) -
Takahiko Iriyama, Nobuyoshi Imaoka1996 Volume 43 Issue 1 Pages 59-65
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSWe discovered a new compound Sm2Fe17N3 in 1987 through the investigation of the structural and magnetic properties of Fe-N-X ( where X denotes an additive element ). The Sm2Fe17N3 is a new type of magnet material which is prepared by introducing nitrogen atoms into the interstitial sites of the Sm2Fe17 crystal under a nitrogen-containing atmosphere at elevated temperatures. The Sm2Fe17N3 shows excellent intrinsic magnetic properties (saturation magne-tization Ms = 1.57 T, the anisotropy field Ha = 21 MA/m and Curie temperature Tc = 746 K). The value of the theoretical maximum energy product, (BH)max amounts to 490 kJ/m3, being a match for the one of the Nd2Fe14B. We have succeeded in developing high performance Sm-Fe-N bonded-magnets; compression-molding magnet with (BH)max of 160 kJ/m3 and injection-molding magnets with 110 kJ/m3 have been fabricated so far. Mn-added Sm-Fe-N compacted powder magnet comprised of coarse powder has also been obtained. The Mn-added magnet has good thermal stability and excellent oxidation-resistance.View full abstractDownload PDF (431K) -
Koichiro Morimoto, Seiro Yahata, Hiroshi Nagai1996 Volume 43 Issue 1 Pages 66-71
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe addition of organic binder in a small amount improves the compressibility and compactibility of Sm-Co magnet alloy powders. However, impurity carbon which comes from the binder is thought to lower magnetic properties of the sintered magnets. In this study, the relationships between the resid-ual carbon content and magnetic properties in SmCo5 and Zr containing Sm2 Co17 magnets have been studied varying the amount of the binder. Effects of thermal debinding atmosphere on binder removal have been also investigated. When the green compacts were debound in vacuum atmosphere, the carbon content of the magnets increased with increase of the binder addition, which decreased coercivities of the magnets markedly. It was observed that carbon forms SmCoC2 and ZrC carbides in SmCo5 and Sm2Co17 magnets respectively. Thermal debinding treatment in hydrogen atmosphere was found to be very effective for removing the binder and reducing the carbon content in the mag-nets. In the binder addition ranges of the present study, the magnets produced through use of this debinding treatment have exhibited nearly the same magnetic properties as those of the magnets made from the powders without the binder.View full abstractDownload PDF (4102K) -
Tetsuo Kato, Noriyoshi Kurata, Yu Tomioka, Katsushi Kusaka1996 Volume 43 Issue 1 Pages 72-77
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSInfluence of the silicon content on the AC magnetic property was studied on the sintered 18Cr-2Mo-Fe magnetic alloy. The highest DC and AC magnetic properties were attained at the content of two-percent silicon. The lowering of the properties was observed at the three-percent silicon or above. The density and the DC magnetic property of sintered alloy was improved with the rise of sintering temperature, but the AC magnetic property indicated a decrease after an increase. This may be attributed to the change of the electrical resistivity originated in the porosity. The highest DC magnetic property and the increase of electrical resistivity are believed to be caused by the improvement of AC magnetic property at the content of two-percent silicon. The lowering of AC magnetic property above three-percent silicon may be due to the decrease of density resulted from the decrease of the press-compatibility.View full abstractDownload PDF (527K) -
Shin-ichiro Ishibashi, Toshihiko Sato, Masaru Yokoyama, Koichi Haneda, ...1996 Volume 43 Issue 1 Pages 78-83
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSBoilers are used to generate steam in many fields such as building and thermal power generation. Products from water evaporation adhere to boilers and their piping as scale or precipitate as sludge, obstructing the flow of steam to lower the thermal efficiency of steam. The detailed data on ferric substance in compositions of such scale and sludge are not well known yet. The author have reported about detailed results of studies emphasizing ferric substance in boilers and their piping used for heating building with steam of 100°C. To clarify the compositions of such substance, we have studied boilers that supply high temperature steam of 180°C to high-rise buildings, mainly investigating the ferric substance in boilers and piping. What has attracted our attention in the study is the fact that ferromagnetic magnetite (Fe3O4) and weakmagnetic hematite (α-Fe2O3) accounted for about 98% of the substances. The average grain sizes of magnetite and hematite were about 105 nm and 160 nm respectively, being larger than those of the heating boilers due to the higher steam temperature. The saturation magnetization was about 79 emu/g, and 82 emu/g when corrected for nonmagnetic layer, being close to the bulk magnetite.View full abstractDownload PDF (1538K) -
Masateru Nose, Takekazu Nagae, Masaru Yokota1996 Volume 43 Issue 1 Pages 84-88
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFe-Si-ZrO2 composite powders were prepared by mechanical alloying using vibrating ball mill under Ar atmosphere. The magnetic properties and thermal stability for Fe-Si-ZrO2 composite powders were investigated by mesns of VSM, DSC and X-ray diffraction. The addition of Si increased the coercivities, He for Fe-ZrO2 composite powders as much as 130-150% of those for the powders without Si against expectation. On the other hand, X-ray diffraction patterns for annealed sample showed that the addition of Si supress the precipitation of ZrO2 from Fe matrix and the coarsening of crystallite size. These results are thought to be due to the lameller structure of Si in Fe matrix.View full abstractDownload PDF (275K) -
Hidehiko Kobayashi, Takashi Ikeda, Takashi Mitamura, Koichi Kakizaki, ...1996 Volume 43 Issue 1 Pages 89-94
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSPreparation conditions and formation process of magnetic particles, Fe3O4, γ-Fe2O3, ε-FexN and γ'-Fe4N were studied by the pyrolysis of ferrous oxalate derived from FeSO4 and (NH4)2C2O4 at temperatures of 300-600°C in various atmospheres such as air, Ar gas, CO2 gas and NH3 gas. The resulting product from the pyrolysis of the ferrous oxalate at 350°C in various atmospheres was a reactive Fe3O4, and γ-Fe2O3 and ε-FexN were prepared at heating the Fe3O4 at 350°C in air and at 500°C in NH3 gas, respectively. The preparation conditions of single phase Fe3O4, γ-Fe2O3, ε-FexN and γ'-Fe4N fine powders from the ferrous oxalate were as follows: (1)Fe3O4 were prepared by heating both at 350-600°C for lh in CO2 gas and at 350-450°C for lh in Ar gas. (2) γ-Fe2O3 was prepared by heating at 350°C for lh in air. (3)ε-FexN was prepared by heating at 500°C for 2h in NH3 gas. (4)γ'-Fe4N was prepared by heating at 600°C for 2h in NH3 gas.View full abstractDownload PDF (2743K) -
Shinichi Kikkawa, Takashi Ohmura, Hideyuki Sugiyama, Fumikazu Kanamaru ...1996 Volume 43 Issue 1 Pages 95-100
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSFormation of iron nitrides, especially Fe16N2, was investigated by nitrogen ion implantation for α-Fe sheet. The implanted nitrogen was lost during the process in the high energy implantation because of the thermal instability of iron nitrides. N+ ion implantation with a beam voltage of less than 100keV and its current of less than 5μA was effective for the Fe16N2 formation. Successive annealing in vacuum at 100°C improved its crystallinity. The formation was explicitly detected by XRD for thin film with an incident beam angle of 1 degree. It was also observed on the N+ ion implantated α-Fe(211) preferred oriented thin film with a thickness of about 1μm deposited on capton film by rf-sputter deposition. The presence of Fe16N2 was detected by XRD, but Mossbauer spectroscopy did not show clearly its presence in the as implanted product. Further annealing is necessary to obtain a well crystallized Fe16N2.View full abstractDownload PDF (310K) -
Hideo Oka1996 Volume 43 Issue 1 Pages 101-105
Published: January 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn this paper, the author reports the experimental results on the internal structure has been done for the magnetic woods, which are made from five kinds of broad-leaved trees or seven kinds of conifers by the sinking of magnetic fluid into them under a pressure, in order to learn the inpregnation.
The measurement results of do magnetization characteristics of these magnetic wood are also reported.View full abstractDownload PDF (941K) -
Hideo Oka1996 Volume 43 Issue 1 Pages 106-110
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn this paper, the author reports on the manufacturing procedure of a wood magnet made of a mixture of wood powder and permanent magnet powder(SnCo) with epoxy resin as the bonding a gent.
The experimental results of do manetiza-tion characteristic of wood magnet which have different mixing ratio of the wood powder and permanent magnet powder are reported. The results such as re manent flux density, coercitive force and maximum energy product show the performance appreciation of the wood magnet compare to those of compound magnets such as rubber magnet and plastic magnet.View full abstractDownload PDF (178K) -
Katsushi Kusaka, Tomio Kohno, Mitsuaki Asano1996 Volume 43 Issue 1 Pages 113-117
Published: January 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe objective of this work is to elucidate the rheological behavior and then to optimize the properties of plastisols loaded with 316L water- and gas-atomized powders, as feedstock of Metal Injection Molding (MIM) process.
The results obtained were summarized as follows:
(1) Judging from powder/binder mixing torque, mixture viscosity is greatly influenced by powder characteristics (shape, size) and generally, related to its tap density.
(2) Practically, water-atomized powder (irregular) needs thermoplastic binder approximately 2.5wt% more than gas-atomized one (spherical) to prepare the optimal feedstock.
(3) Powder plastisols show Bingham-type flow behavior and consequently, give almost the same viscosity-shear rate relationship all over the powders for the optimal solids loading (Φo).View full abstractDownload PDF (2419K) -
Toshio Shimoo, Toshihide Hayatsu, Kiyohito Okamura1996 Volume 43 Issue 1 Pages 118-121
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe deterioration of Nicalon by high-temperature heat-treatment was investigated. Early in the pyrolysis, the violent evolution of pyrolytic gases (SiO and CO) caused surface imperfections and great loss of strength of Nicalon. During the subsequent pyrolysis, the strength remained practically unchanged. At the last stage of the pyrolysis, although the evolution of gases became gradual, the strength was drastically reduced because of the coarsening of β-SiC crystals. The strength of the low-oxygen SiC fiber, which was prepared by the electron-irradiation curing method, was dependent solely on the crystal size of SiC, because of the mild generation of pyrolytic gases.View full abstractDownload PDF (1749K) -
Yoshihiko Kunieda, Junichi Okabe, Kazumi Murakami, Tetsuo Inoue, Hidey ...1996 Volume 43 Issue 1 Pages 122-127
Published: January 15, 1996
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSThe sintered porous nickel is very important as electrode materials and have been used widely. In this work, the effect of surrounding pressure under capsule-free HIP (CFHIP) and vacuum on sintering behaviors concerned with the volume shrinkage, the relative density and the surface microstructure of the porous Ni sintered for 1 hour at 1073K or 1173K were investigated. The results obtained are as follows. The volume shrinkage and the relative density, as a function of the relative density before sintering, of the porous Ni sintered under CFHIP became larger than for ones sintered under vacuum at each of the sintering temperatures. These sintering behaviors of the porous Ni formed from the smaller particle size powder were accelerated under the both surrounding pressures, CFHIP or vacuum, and at both sintering temperatures. In case of under CFI-IIP, the neck growth of Ni powder was promoted at either sintering temperature as compared with under vacuum and this fact was emphasized at the elevated temperature. And the surface of porous Ni sintered under CFHIP was made smoother than ones sintered under vacuum for every Ni powder and at the each sintering temperature.View full abstractDownload PDF (6316K) -
Microstructures and Mechanical Properties of TiB2-SUS316L Cermets Prepared by Pressureless SinteringDong-Gil Ahn, Akira Kawasaki, Ryuzo Watanabe1996 Volume 43 Issue 1 Pages 128-133
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe densification behaviour of different TiB2 powders sizes of TiB2-(3-25vol%)Stainless steel (SUS316L) cermets was examined during pressureless sintering in argon atmosphere. Microstructures of sintered cermets and mechanical properties such as Vickers hardness, bending strength, fracture toughness and Young's modulus were also investigated. When fine TiB2 powders were used, TiB2-SUS cermets with good sinterability and enhanced meccanical properties could be produced. Full density sintered cermets were obtained, and a new phase, Fe2B, was observed in 5-15vol%SUS cermets. The highest hardness values of 21GPa and the Young's modulus of 498GPa were obtained at 5vol%SUS. The highest bending strength of 1290MPa, was obtained for the 15vol%SUS cennet. Iron besides and titaniume oxides in sintered cemrets are connected with the presence of B, O impurities in TiB2 powders. In cider to improve mechnical properties, finer powders with low oxygen and carbon content, are desirable.View full abstractDownload PDF (2743K) -
Shigetoshi Muranaka1996 Volume 43 Issue 1 Pages 134-137
Published: January 15, 1996
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIndium oxide films were reactively deposited on MgO and CaO films at substrate temperatures of 25-100°C. The influence of the MgO and CaO substrates on the film structure and the physical properties was investigated. The Crystallinity of the films was much improved on the CaO substrates at 100°C, although an amorphous phase was still contained in the films to some degree. With improvement of the crystallinity, the light transmittance of the films was increased. At 60°C, the effect of the CaO sub-strates on the film structure was very small. The MgO substrates had little effect on the growth of crystalline films.View full abstractDownload PDF (205K)
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