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Volume 65, Issue 9
Displaying 1-27 of 27 articles from this issue
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Masayuki Sato, Hiroyuki Kaneko2001 Volume 65 Issue 9 Pages 767-770
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn order to electrochemically control oxygen pressure at low temperatures below 400°C, a planar zirconia oxygen pump-gauge with Ag electrodes for a pump and a sensor was constructed by attaching a thin plate of YSZ electrolyte to a low thermal expansion alloy vessel. The sensor worked precisely to a lower limit of 250°C and the pump quantitatively introduced oxygen throughout a wide range of oxygen pressures at 400°C. As a result, this device responded well to both the stationary-injected and pulse-injected oxygen.View full abstractDownload PDF (300K) -
Hirofumi Sumi, Masaaki Kato, Yoichi Nishino, Shigeru Asano, Uichiro Mi ...2001 Volume 65 Issue 9 Pages 771-774
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSWe have measured the temperature dependence of electrical resistivity, specific heat and magnetization of (Fe1−xVx)3Al alloys with V compositions 0.33≤x≤0.36. The near-stoichiometric Fe2VAl (x=0.33) exhibits a semiconductor-like behavior with the resistivity reaching 30 μΩm at 4.2 K. When the V composition deviates slightly from stoichiometry, the low-temperature resistivity is reduced to only 3 μΩm for x=0.34, showing a positive slope in its temperature dependence below 300 K, but turns to increase remarkably for x>0.34. Plots of the specific heat over temperature, C⁄T, versus T2 for x=0.33 show an anomalous upturn with decreasing temperature, and the magnetization data provide an evidence of local moment magnetism. In contrast, the enhancement of the specific heat and magnetization is considerably suppressed for x=0.34, being consistent with recent band calculations which predict that Fe2VAl is a nonmagnetic semimetal. The semiconductor-like resistivity behavior is most likely caused by strong spin fluctuations of Fe impurities on the nominally V site in Fe2VAl.View full abstractDownload PDF (280K) -
Mari Nishi, Yuji Yamasaki, Kenichi Takagi2001 Volume 65 Issue 9 Pages 775-778
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe liquid phase sintering behavior of the Mo2NiB2 base cermets was investigated by using Ni-5 mass%B-53.25 mass%-0, 5, 10 mass%Mn model cermets.
Mo2NiB2 complex boride base cermets consisting of the Mo2NiB2 hard phase and Ni base binder were produced from powder mixtures of Ni2B, Mo2B5, Mo, Ni and Mn. Full densification of the cermets was achieved by the quasi-eutectic liquid phase between the Ni binder and Mo2NiB2 hard phase associated with a diffusion reactive sintering process. Orthorhombic Mo2NiB2 was formed during solid state sintering as a result of the reaction among NiB, Ni and Mo for the compacts without Mn and the reaction among MoB, Ni and Mo for the Mn containing compacts. Additions of Mn resulted in increasing the Mo2NiB2 forming temperature and decreasing the eutectic liquid phase formation temperature between Ni binder and the Mo2NiB2 hard phase. The size and dispersion of the boride phase changed depending on the sintering conditions, those are the liquid phase formation temperature and the amount of the liquid phase during sintering.View full abstractDownload PDF (513K) -
Natsuo Onodera, Moe Aono2001 Volume 65 Issue 9 Pages 779-782
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThis paper tries to predict diffusion coefficients of impurity atoms in copper and silver from the basic properties of the solute atoms. For this purpose a multiple regression analysis was made on the diffusion data selected from the JST Diffusion Database. The coefficients of determination (R2) for the activation energy of diffusion were 0.71 for Cu solvent and 0.92 for Ag solvent, and those for the frequency factor were 0.27 and 0.77 for Cu and Ag solvents, respectively. The position in the periodic table and the electronegativity of solute atoms were found to be highly significant independent variables. The present model shows an ability comparable to Le Claire’s electrostatic model in prediction of the activation energies for impurity diffusion in Cu and Ag.View full abstractDownload PDF (248K) -
Seiji Fukuyama, Dongsheng Sun, Kiyoshi Yokogawa2001 Volume 65 Issue 9 Pages 783-786
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSTensile properties of Nb were investigated in 1.1 MPa hydrogen and argon in the temperature range of 473∼1273 K. The effect of temperature on hydrogen environment embrittlement (HEE) of the material was also examined. The results obtained are as follows:
HEE occurred at the temperature range of 673∼1073 K and showed maximum at 800 K. In this temperature range, hydrogen decreased elongation and ultimate tensile strength of the material with decreasing the strain rate. Cleavage fracture together with the striations was observed on the fracture surface in hydrogen, while ductile rupture was observed in argon. No hydride was observed in the specimen fractured in hydrogen by X-ray diffraction. It is discussed that HEE of Nb occurred at this temperature range by the similar mechanism of HEE of iron without hydride near room temperature.View full abstractDownload PDF (850K) -
Wataru Takakura, Mitsuhiko Matsui, Akihiro Yamada, Yuji Ueda2001 Volume 65 Issue 9 Pages 787-790
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSRecently, magnetoresistance effects have been found in the metal oxides produced by variety of methods. We have investigated the magnetoresistance(MR) effect of magnetite(Fe3O4) produced by Ball Milling. MR ratio was increased from 1.4% to 2.2% after ball milling for 10 hours. After annealing at 623 K for 1 hour, MR ratio increased to 3.3%. It seems that the origin of the magnetoresistance effects for the magnetite Fe3O4 is related to the precipitation of Fe2O3. MR ratio increased monotonically with decreasing of temperature, and showed 4% at the temperature of 100 K.View full abstractDownload PDF (373K) -
Yuki Matsuoka, Masahiko Kakumoto, Keiichi N. Ishihara, P. Hideo Shingu2001 Volume 65 Issue 9 Pages 791-794
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe unidirectional solidification is one of the methods for the purification of materials. In this method, the problem that the solute is trapped into the solid during the solidification can be encountered. To overcome this problem, the method of unidirectional solidification under fluid flow has been developed and was applied to the desalinization, where concentrations of salt, relative velocity of fluid flow against solid, V, and solidification rate, R, were employed as experimental parameters. The effective distribution coefficient, keff, defined as the ratio of the solute concentration in solid to that in liquid, was introduced to evaluate desalinization. The value of keff became smaller as the value of V increased and that of R decreased. When the conditions of V and R were constant, the value of keff became larger with increasing the concentration of salt. From the crosssectional view of the microstructure for solid, it has been found that the crystal grows along the centrifugal direction and the size of crystal cell decreases with increasing the concentration of salt. Moreover, it has been found that the logarithm of keff can be expressed as a function of RV−0.5 when the concentration of salt is low. It will be shown that the boundary layer theory can be applied to the system.View full abstractDownload PDF (473K) -
Satoko Abe, Takahiro Kadokura, Tetsumori Shinoda, Yoshihiro Seimiya2001 Volume 65 Issue 9 Pages 795-798
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn this study the compositional dependence of Tc was investigated for A15 type V3Ga compound which shows a comparatively high value of Tc among metallic superconductors, and the results were discussed in terms of crystal structure determined by X-ray diffraction.
It has been found that V3Ga compounds keep the same Tc in the V-rich compositional range as that at the stoichiometric composition. This result is quite different from the previously reported ones, and is mainly attributed to the difference in annealing time.
Detailed analysis by X-ray diffraction for different compositions of V3Ga proved that the long range ordering for the V site is strongly related to the compositional dependence of Tc rather than the total long range ordering of V3Ga. About compositional dependence of lattice parameter, lattice constant a increases as Ga-composition increases. In the V-rich compositional range, a increases a little. These have been also discussed on the basis of the results of lattice spacing. It is concluded that the Tc of V3Ga is associated with both the long range ordering of V site and the atomic spacing of the V-chain.View full abstractDownload PDF (275K) -
Natsuro Hobara, Shigenobu Asada, Maxim Kuznetsov, Toru Izumi, Xin Yao, ...2001 Volume 65 Issue 9 Pages 799-802
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn our study, we have developed coated conductors using the LPE (Liquid Phase Epitaxy) method. We found that MgO saturated solution can prevent the Metal solution reaction. It is also found that double LPE structured films on MgO crystals exhibit the Tc value of 90 K. We succeeded in producing a film consisting of YBa2Cu3Oy/YBa2(Cu, Mg)3Oy by LPE growth on MgO buffer/Hastelloy. However, 1st LPE layer was unstable during the second LPE growth. Therefore, we discussed the thermodynamics about the LPE layer growth, and realized that the lower growth temperature is advantageous for the second LPE. Finally, we succeeded in producing the double LPE layer structure without meltback of the 1st layer.View full abstractDownload PDF (452K) -
Kohta Asano, Toyokazu Tabata, Yoshihiro Yamazaki, Yoshiaki Iijima2001 Volume 65 Issue 9 Pages 803-806
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSDiffusion of protium in the α phase (solid solution), the α′ phase (α phase dehydrided from the β phase) and the β phase (hydride) of LaNi5-H alloys was studied by the desorption method. It was observed that the diffusion coefficient of protium in the β phase was a little higher than that in the α phase and that these were much higher than that in the α′ phase. The difference between the diffusion coefficients in the three phases is attributed to the difference in the protium concentration between the α phase and the β phase and to the difference in the trapping density between the α phase and the α′ phase.View full abstractDownload PDF (275K) -
Hirofumi Homma, Hideyuki Saitoh, Toshihei Misawa, Toshiyuki Ohnishi2001 Volume 65 Issue 9 Pages 807-810
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSHydrogen distribution in Ti-Cr alloys with composition of Ti50Cr50 and Ti30Cr70 around TiCr2 Laves phase have been quantitatively observed by the tritium radioluminography, and the relation between the hydrogen distribution and microstructure has been examined. Hydrogen concentration in these alloys has been varied depending on the heat treatment conditions. The heat treated specimens at 1300°C has shown the highest value of hydrogen concentration for both alloys as 0.75 mol% for Ti50Cr50 alloy and 4.2 mol% for Ti30Cr70 alloy. This is attributed to the network structure of BCC phase formed by the heat treatment. The highest value of hydrogen concentration in Ti30Cr70 alloy heat treated at 1300°C has suggested that this specimen has an excellent initial activation property.View full abstractDownload PDF (519K) -
Yasuyuki Miyazawa, Yoshitake Nishi2001 Volume 65 Issue 9 Pages 811-814
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSBy using student evaluation method developed in Tokai University, faculty developments of experimental subject were performed for experimental subjects in Department of Materials Science in Tokai University. It was succeeded for sophomore student just on time from 1994 to 1996. After that, social contributions of the experimental subjects were confirmed by using the evaluation method for the students after graduation on March in 2001.View full abstractDownload PDF (246K) -
Haru-Hisa Uchida, Nobukata Kutsuzawa, Yasuyuki Miyazawa, Yoshitake Nis ...2001 Volume 65 Issue 9 Pages 815-818
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn this study, developing senses of ethics and duty of engineers for well-being and welfare of human beings were examined by a lecture on modern civilization II, where the lecture was considered to be suited for satisfying the aim of Japan Accreditation Board for Engineering Education (JABEE). At the end of the semester, questionnaire was given to two kinds of classes, one consisted of general students and the other was a class for students from companies. From the results, most students could realize the importance of the senses, which resulted in that the lecture could be a practical educational method of JABEE.View full abstractDownload PDF (325K) -
Eri Miura, Liu Jie, Ikuya Watanabe, Yasuhiro Tanaka, Takanobu Shiraish ...2001 Volume 65 Issue 9 Pages 819-822
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSMicrostructure observation of peeling plane of the fusing porcelain with titanium was performed by SEM-EDX. From the results of the bend test, bonding strength of the degassed sample using bonding-porcelain is higher than that of degassing-free and bonding-porcelain-free sample. From SEM-EDX observation of the peeling plane, the sample using the bonding-porcelain shows good reactivity with the porcelain, and many hollows out of the porcelain side were observed. However, chemical composition of peeling plane indicates that peeling plane is formed by mainly titanium. Microstructures of the sample with and without bonding-porcelain are obviously different, which indicates that the difference of reaction product in interface region. From the result of the cross-sectional observation of the fused porcelain/titanium interface, it was suggested that the peeling at interface between titanium and porcelain causes at the oxygen-dissolved titanium and/or titanium oxide phase which diffuses to the porcelain side.View full abstractDownload PDF (996K) -
Takashi Asaka, Teruko Katsura, Haru-Hisa Uchida, Akira Tonegawa, Yasuy ...2001 Volume 65 Issue 9 Pages 823-826
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSIn order to enhance an ability of life saving and emergency management for students in huge campus, crisis management education and safety management education were performed for students of science and engineering in Tokai university Shonan campus. After the evaluations of the safety level of laboratory and facilities, the laboratory safety manual and videotape were prepared for whole students at different departments. Subsequently, half-hour guidance for freshmen and two-hour guidance for graduate students were performed using these manual and videotape. Based on the results of questionnaire survey, most of students (over 90%) can see the necessity of the emergency management education. Furthermore, to realize student’s opinions, lecture on emergency management, and CPR (Cardio Pulmonary Resuscitation) training were opened.View full abstractDownload PDF (264K) -
Takeshi Kubota, Yasubumi Furuya, Teiko Okazaki, Munemi Michigami2001 Volume 65 Issue 9 Pages 827-830
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSFerromagnetic shape memory alloy (FSMA) is recently known as a new type of magnetically driven solid state actuator material, which has large strain as well as a quick response to the mechanism of re-arrangement of martensite twin by magnetic field. In this study, Fe-29.6 at%Pd alloy ribbons formed by rapidly solidified, melt-spinning methods were studied. Samples showed strong anisotropy and large magnetostriction, ε=600∼800×10−6 at nearly perpendicular direction to its plate surface (θ=90°) at room temperature. The ε vs. temperature, T curve had a maximum at 370∼400 K, then decreased steeply with increasing T. Magnetization, M and applied magnetic field, H loops also showed anisotropic behavior similar to ε vs. H curve. It was found that the coercive force, Hc=6.1 kA·m−1, at θ=90° decreased steeply in the range of 293 to 320 K and then it reached to constant, 2 kA·m−1 with T. Since the remarkably decrease of Hc is caused by the disappearance of the obstacles against magnetization, i.e. martensite twin variants in the lower temperature phase, it is suggested that Af equals to about 320 K. By X-ray diffraction analysis, the Af from fct to fcc is 330 K, which seems to coincide with the result by the Hc vs. T curve. Shape memory effect vs. T curve had two sharp increasing points near 320 K and 400 K which correspond to the phase transformation temperatures estimated by X-ray, Hc and ε, respectively.View full abstractDownload PDF (340K) -
Hiroshi Tsuda2001 Volume 65 Issue 9 Pages 831-834
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSAE signals propagate as extensional and flexural plate modes in thin plates. The relative amplitude of the two modes depends on the directionality of AE source motion. It has been reported that the directionality of AE source motion can be determined by distinguishing the dominating mode of plate waves. In the present study, response of Michelson interferometric fiber-optic sensors to AE with either in-plane or out-of-plane motion was investigated. AE signals simulated by pencil lead break were given to a thin unidirectional carbon fiber-reinforced plastic plate. The resulting plate waves were detected with surface-bonded interferometric fiber-optic and piezoelectric AE sensors. Responses of both sensors were compared and frequency characteristics of signals were evaluated by the Fast Fourier Transform. The directionality of source motion could be determined from the interference signal behavior in the beginning of response.View full abstractDownload PDF (348K) -
Yasuhiro Kawaguchi, Noriko Nakamura2001 Volume 65 Issue 9 Pages 835-842
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSAiming at non-destructive evaluation of fatigue stored in type 316 stainless steel which is mostly used in the primary water line of pressurized water reactor (PWR), we tried to apply positron annihilation lineshape analysis to fatigue damage. By making use of 68Ge as a positron source, an energy spread of annihilation gamma ray peak from stainless steel specimens was measured. We prepared stress controlled fatigue specimens and strain controlled fatigue specimens, and then we investigated the relation between fatigue life and a non-destructive parameter of lineshape analysis defined as S-parameter and compared the microstructure of the fatigue specimens with the S-parameter. As a result, it is seen that there exists a good correlation between the S-parameter and the fatigue life; the S-parameter increases with dislocation density monotonically. The relation between the S-parameter and the fatigue life in the stress controlled fatigue is different from that in strain controlled fatigue. The S-parameter in the latter increases faster in early stage than that in the former. In the case of stress controlled fatigue, the change in the S-parameter does not depend on stress amplitude in the range from 200 to 250 MPa. In the case of strain controlled fatigue, the change in the S-parameter does not depend on strain amplitude in the range from 0.25 to 0.31%. Finally we succeeded in demonstrating systematic data to evaluate the fatigue damage in type 316 stainless steel.View full abstractDownload PDF (1349K) -
Takashi Yamasaki, Hiroyuki Miyamoto, Takuro Mimaki2001 Volume 65 Issue 9 Pages 843-847
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSCorrosion fatigue behavior of ultra-fine grained (UFG) copper produced by Equal Channel-Angular Pressing (ECAP) technique has been studied in 1 kmol/m3 NaNO2 aqueous solution. A significant increase of the number of cycles to fracture was observed for UFG copper. In this case, two factors were considered. First, persistent slip bands (PSBs), which were the preferred areas of anodic corrosion in aggressive solution, were not formed in UFG copper. Second, UFG copper was less susceptible to intergranular corrosion than polycrystalline copper.View full abstractDownload PDF (1020K) -
Nobuyuki Mori, Keisaku Ogi2001 Volume 65 Issue 9 Pages 848-851
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSMany analytical and numerical studies have been performed on microsegregation and prediction of second phase in solidification structures of alloys. They have both advantages and disadvantages especially on the applicability of variable partition ratio(k) of solute and diffusion coefficient(D) in the solid. A new progressive-type solidification equation: (CLi⁄CLi−1)=[{1−(1−B·ki−1)fsi}⁄[{1−(1−B·ki−1)fsi−1}](ki−1−1)⁄(1−Bki−1), which has parameter (B) including variable k and D in the solid, is proposed in this paper. Parameter B is given in each progressive solidification model (modified Flemings model, Clyne-Kurz model, or Ohnaka model). The difference in B-values among the above models are small when D-value is relatively small. The composition changes in liquid and solid phases during solidification are calculated by this equation. The solidification-passes of various Al-Ti-Cr alloys, which crystallized (Al, Cr)3Ti as the primary phase, are analyzed by the above method by using the data of Al-Ti-Cr phase diagram and k-values (: functions of composition) and diffusion coefficient obtained by experiment. The calculated results agree well with important aspects of experimentally obtained solidification microstructure such as non-equilibrium eutectic phases.View full abstractDownload PDF (378K) -
Takeshi Fukuda, Moritaka Hida, Akira Sakakibara, Yoshito Takemoto2001 Volume 65 Issue 9 Pages 852-857
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSBonding states near the BCC(Fe) edge dislocation core based on the Peierls-Nabarro dislocation model have been studied by discrete variational (DV)-Xα method. The slip systems are {112}⟨111⟩ and {110}⟨111⟩. The molecular orbital calculation for the cluster models with 32 atoms belonging to the perfect crystal and Peierls edge dislocation core models were carried out for estimating bond order and net charge distribution among atoms in the cluster models. In {112}⟨111⟩ slip system total bond order between the nearest neighbor atoms of the dislocation model was found to be larger than that of the perfect crystal model. On the other hand, total bond order of the second neighbor atoms in dislocation model was a little smaller than that in the perfect crystal model. It was also found that there was asymmetry in the bond order between the left side and the right side of the (110) plane which contains the core atom of dislocation. Net charge in the dislocation model was larger than that in the perfect crystal model. Almost the same results were also attained for the {110}⟨111⟩ slip system.View full abstractDownload PDF (561K) -
Makoto Toho, Hideyoshi Kimura, Shuji Yamada2001 Volume 65 Issue 9 Pages 858-867
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSFlourescent lamp is the main light sources at the lighting field. It has good efficacy, but the energy conversion is only 25% level. It is requested to improve its efficacy for the further energy saving because the energy consumption by lighting industry is about 20% of the total energy demand. The key issue for drastic efficacy improvement is the phosphor technology. Since phosphor has been researched and improved on the bases of the one-photon emission theory, even the highest phosphor energy efficacy (transition rate on UV to visible) is under 50%. However, 254 nm UV photon of Hg discharge has 4.9 eV energy, which could be transferred to two visible photons. It is expected that some metal atoms have possibility of two-photon visible emission for 254 nm light excitation. The authors researched the feasibility of two-photon emission approach provisionally called “atomic phosphor”, with atomic-like emission by the metal atom isolated in the matrix. The authors could succeed in isolating the iron atom in the silica matrix through the sol-gel fabrication method, under the room temparature, though the fluorescence was not desired two-photon emission but continuous deep blue spectrum. The paper reports the research outline of the new phosphor with the metal atom activator isolated in the matrix.View full abstractDownload PDF (646K) -
Hideaki Kuramoto, Kazuhiro Matsugi, Tomei Hatayama, Osamu Yanagisawa2001 Volume 65 Issue 9 Pages 868-873
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSBehaviors of monosized spherical copper powder particles of 550 μm average diameter in the powder compact was observed under optical microscope during single-pulsed electric discharge for 500 ms. The morphologies of necks between powder particles were observed under scanning electron microscope and diameters of necks were measured. The results obtained were summarized as follows: It was confirmed that if the spark occurs or not depends on the pressure and pulsed current density. The spark at the interparticle contacts occurred more frequently, as the pressure was smaller and the current density was larger. Each particle was joined together by melting where the spark occurred. However, regardless the spark was observed or not, the necks were formed at the interparticle contacts and diameters of necks increased with increasing pulsed current density. It was suggested that microscopic spark, melting and vaporization occur due to extremely high temperature by the local heat generation at the interparticle contacts in the initial stage of compaction.View full abstractDownload PDF (860K) -
Kazuhiro Kurahashi, Jiro Takebe, Takatoshi Saeki, Masahiro Okumiya, Yo ...2001 Volume 65 Issue 9 Pages 874-879
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe gas-carburizing atmosphere for surface treatment of steel can be regulated using the carbon potential (CP) which is obtained by measuring dew point, O2 concentration or CO2 concentration. Since zirconium oxide O2 sensors are easier-to-handle and respond better than others, they are generally used when measuring O2 concentrations. Methane is the main component of natural gas and is stable at high temperatures, so that traces of it tend to remain in furnaces. The remaining methane decomposes on the O2 sensor tip, and the O2 concentration around the sensor tip decreases. Therefore the measurement of carbon potential with O2 sensors has been considered to be difficult, when natural gas is used as the enriched gas. In this study, carbon potential control using O2 sensors for gas-carburizing atmospheres enriched with natural gas, was examined. A new method for regulating CP was also examined. It utilizes the difference between CP calculated from the CO2 concentration and that calculated from the O2 sensor value, while preventing sooting.
With these methods for regulating the gas-carburizing atmosphere, seasoning time and gas consumption could be reduced.View full abstractDownload PDF (472K) -
Kazunao Furumata, Osami Seri2001 Volume 65 Issue 9 Pages 880-887
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSThe electrochemical experiments and metallurgical observations have been made to estimate the chloride ion concentration in the pitting cavity on the aluminum 1100 specimens which are corroded in 0.1 kmol/m3 NaCl solution for 3.9 Ms. The estimation is based on the experimental fact that the corrosion potential (open-circuit potential) of the 1100 specimens coincided with the pitting potential for all period of immersion. It is indicated that the value of the chloride ion concentration in pitting cavity is equivalent to that of 0.46∼0.61 kmol/m3 AlCl3 solution as a substitutive solution of the pit solution.View full abstractDownload PDF (1155K) -
Satoshi Itabashi, Katsunori Yamaguchi, Kazuo Kameda2001 Volume 65 Issue 9 Pages 888-892
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSEmf of galvanic cells with zirconia solid electrolyte was measured to determine the activity of indium in the liquid In-Sb-Ag and In-Sb-Te systems in temperature ranges from 970 to 1280 K for the In-Sb-Ag system and for the In-Sb-Te from 870 to 1260 K. The following cells were used: Pt/Ni, NiO|ZrO2(+CaO)|In-Sb-Ag, In2O3/Re/Pt, Pt/Ni, NiO|ZrO2(+CaO)|In-Sb-Te, In2O3/Re/Pt. The isoactivity curves in the liquid In-Sb-Ag and In-Sb-Te systems at 1100 K were derived from combining the activity data of the In-Sb, In-Ag and In-Te binary alloys. The shape of isoactivity curves in the liquid In-Sb-Ag exhibits a slight bend to the Sb-Ag binary side, and those of the liquid In-Sb-Te gather from the whole composition range of the In-Sb binary alloy to the intermediate composition of the In-Te system.View full abstractDownload PDF (403K) -
Masaru Yokota, Fuminori Sugaya, Xiao Qing Hang, Tang Kun He2001 Volume 65 Issue 9 Pages 893-895
Published: 2001
Released on J-STAGE: April 24, 2008
JOURNAL FREE ACCESSRecently, we have got a chance to collect a small piece of the ancient bronze mirror, which had been manufactured in the middle or the late Chinese Han period. To investigate it’s metallurgical properties by means of optical microstructure observation and various instrumental analyses. From these investigations, we have detected the crystalline anomalies in the corroded layer alias “bronze disease” layer in the clay for the ancient bronze mirror. Results obtained were as follows:
(1) The apparent density of the mirror, measured by means of the Archimedes method, tends to decrease with the extent of the corroded layer in the clay.
(2) The semi-transparent thin film formed on the mirror was the crystalline tin oxide (SnO2).
(3) The corroded structural defect alias “bronze disease” layer formed just under the surface of mirror was the amorphous (like) tin oxide, which contains lower Cu and higher Pb contents.
(4) Mechanisms of the formations of the semi transparent thin film on the mirror surface and the amorphous (like) layer in the attacked layer in the clay and the behavior of the copper element should be made clear hereafter.View full abstractDownload PDF (481K)
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