All issues
Volume 70, Issue 3
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
-
Takashi Ando, Yoshio Harada2006 Volume 70 Issue 3 Pages 213-219
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSNa-S(NAS) battery cell are comprised of a negative sodium electrode and a positive sulfur electrode separated by a solid electrolyte made of beta-alumina and housed in a cylindrical aluminum container.
High Cr-Fe alloy surface coatings are applied on the inner walls of cylindrical aluminum containers by atmospheric plasma spraying to prevent a sulfide corrosion. Methods used for applying these coatings and methods used for evaluating polished surfaces were studied. Just after a high Cr-Fe alloy coating is sprayed, the surface contains a considerable amount of unmelted alloy particles and black fine fumes of Cr oxides. This situation causes excessive electric resistance during battery charge and discharge.
Therefore, an automatic polishing method for high Cr-Fe alloy containers using a rotating brush made from piano wire was developed. As a result, most of the fumes on the coatings were eliminated, and by polishing the uneven coating surface, the new metallic surface is revealed.
This makes it possible to control the amount of electric resistance inside the battery.
Also, through a study of polished surface evaluation methods, it was confirmed that it is possible to measure the average amount of contact resistance for sprayed coating surfaces before and after polishing using a surface quality (SQ) meter.
View full abstractDownload PDF (727K) -
Yoshitou Hayashida, Yoshiyuki Takahashi, Takao Ohno, Ikuo Shohji2006 Volume 70 Issue 3 Pages 220-225
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSElectronic products with Sn-Pb solder are being now excluded due to the harmful effect of Pb on the environment. Generally, Sn-Ag-Cu solder is used in place of Sn-Pb solder. In the solder joint, acicular crystals called whiskers often grow. Whiskers often cause a short-circuit problem in a fine-pitch solder joint. In this study, several lead-free solders added with a small amount of various elements were prepared to investigate the effectiveness validity of added elements in restraining whisker growth. The elements effective in inhibiting whisker growth were identified.
View full abstractDownload PDF (649K) -
Rongguang Wang, Keijiro Nakasa2006 Volume 70 Issue 3 Pages 226-232
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSAnodic polarization testing of SUS304 stainless steel was carried out in an aqueous solution of 3.5%NaCl at a potential increasing at a constant rate of 20 mV/min. When the current density reached 2, 10 or 50 A/m2 within the pitting corrosion region, the potential was kept at a constant value for 600 s at each current density. An ultrasonic wave (UW) was applied to the specimen from the beginning of test or just after the potential reached one of these constant values. The current density in these cases was compared with that without the application of UW. The results indicated that when the UV was applied from the beginning of test the current density was not affected by the application of UW in both the cathode and passive regions, but it was decreased when the potential was kept at the constant value after the current density reached 10 or 50 A/m2. Also when the UW was applied after the current density reached 2, 10 or 50 A/m2 and the potential was kept at the constant value, the current density was decreased by the application of UW. At the same time, the number and size of pits were decreased by the application of UW. The reason for the decrease in pitting corrosion was considered to be that UW destroyed the corrosion product on pits and the stirring effect of UW decreased the concentration of hydrogen and chloride ions in the pits, which accelerated the formation of a passive film on the pit wall.
View full abstractDownload PDF (475K) -
Hiroaki Yamamoto, Akio Miyata, Koichiro Koyama2006 Volume 70 Issue 3 Pages 233-237
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSThe standard Gibbs energy of formation of Ni3B2O6 were determined by measuring electromotive forces of the galvanic cell using an Y2O3-stabilized ZrO2 solid electrolyte (YSZ(8)). Ni3B2O6 was prepared by the spray drying method. The cell constructed for measuring the emf was as follows:
Pt|Ni, Ni3B2O6, B2O3|YSZ(8)|O2 in air|Pt.
The electromotive forces of this cell (E/V) were measured as a function of temperature (T/K) as follows:
E=1.214-4.522×10-4 T±2×10-3,
where temperature range was 1193~1393 K. Using this emf, the standard Gibbs energy of formation of Ni3B2O6 (ΔfGo(Ni3B2O6)/J•mol-1) was calculated as follows:
ΔfGo(Ni3B2O6)=-1934000+455.6T±1000
where the standard pressure is 1 bar (100 kPa).
View full abstractDownload PDF (387K) -
Takashi Ogasawara, Kaoru Akazawa, Haru-Hisa Uchida, Yoshitake Nishi2006 Volume 70 Issue 3 Pages 238-242
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSA mechanical mover with hydrogen storage alloy was made up and tested. In former research, a unimorph structure was proposed, in which a silicone rubber with LaNi5 alloy powder distributed was piled up on a pure silicone rubber sheet. Using this structure we succeeded a soft movement of the device by applying hydrogen gas pressure. Because the movement indicated slow response, therefore in this research, we tried to improve the response of the moving device by mixing a catalyst of Pd-Al2O3 powder into the hydrogen storage alloy powder in the rubber. We obtained drastically improved responses in a movement of the device.
View full abstractDownload PDF (407K) -
Noriyoshi Matsuoka, Tempei Tanakamaru, Yoshihito Matsumura2006 Volume 70 Issue 3 Pages 243-245
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSSm-Fe thin films as giant magnetostrictive materials were prepared by d.c. magnetron sputtering process with Ar or mixed Ar-N2 gas. Diffraction peaks of Sm nitride and Fe nitride were observed at 3.8×10-3 Pa N2 partial pressure. With increasing N2 partial pressure, saturated magnetostriction of the Sm-Fe thin films decreased from 1400 ppm to 600 ppm. The maximum value of magnetostrictive susceptibility was showed at 2.3×10-3 Pa of N2 partial pressure. A compression stress with a small addition of N into Sm-Fe thin films may lead to increase of magnetostrictive susceptibility.
View full abstractDownload PDF (294K) -
Hirofumi Ohata, Tadaharu Yokokawa, Toshiharu Kobayashi, Yoshikazu Ro, ...2006 Volume 70 Issue 3 Pages 246-249
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSThis study was carried out to find out the mechanical properties of nickel-base superalloys that affect thermal mechanical fatigue (TMF). TMF tests and high temperature tensile tests were conducted on 28 of Ni-base single crystal superalloys in order to obtain mechanical property data. Based on the experimental data, Multiple regression analysis was performed for the correlation between the number of TMF cycles to failure and the alloy compositions. The multiple correlation coefficient was found to be R=0.84; this indicates that alloy composition has a considerable relationship with the number of TMF cycles to failure. It was also found that the addition of Co, Ru and Al is effective to improve the TMF property.
In addition, another multiple regression analysis was also carried out for the correlation between the number of TMF cycles to failure among high temperature mechanical properties and microstructural parameters.
View full abstractDownload PDF (289K) -
Keishi Nakamura, Shiomi Kikuchi2006 Volume 70 Issue 3 Pages 250-254
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSResistive materials with thermoelectromotive force of 6 to 46 μV/K and temperature coefficient of resistance (TCR) of -26 to +4107×10-6 K-1 were successfully fabricated by using the foil metallurgy pressing method and the stacking and rolling of metallic foils of Cu and Ni. The Cu/Ni multilayer materials showed changes of electrical characteristics with the conditions of heat treatment. The TCR values of the specimens decreased with increase of alloying area at the interface of Cu and Ni layers by heat treatment. On the contrary, the values of thermoelectromotive force for copper increased with the increase of temperature of heat treatment.
This process allows the electrical characteristics to be controlled as required, and the resistance material of a precise resistor for current detection to be made.
View full abstractDownload PDF (416K) -
Hiroyuki Kobayashi, Michelle Salvia, Yoshitake Nishi2006 Volume 70 Issue 3 Pages 255-257
Published: 2006
Released on J-STAGE: March 24, 2006
JOURNAL FREE ACCESSElectron beam irradiation has been reported to be effective for polymer surface modification and on strengthening of inorganic glass. In the present research effects of electron beam irradiation on impact value of glass fiber reinforced polymer (GFRP) were studied. The electron beam irradiation enhanced Charpy impact value at every fracture probability.
View full abstractDownload PDF (285K)
- |<
- <
- 1
- >
- >|