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Volume 28, Issue 4
Displaying 1-6 of 6 articles from this issue
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Kazuhiko Majima, Yoshio Sohama, Hiroyasu Mitani1981 Volume 28 Issue 4 Pages 125-130
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn this experiment, the sintering characteristics of the Ti-50at%Ni binary mixed powder compacts were examined by the dilatometric method, and the homogenization process during sintering was discussed in relation to the internal friction which is a standard for the damping capacity.
The results obtained were summarized as follows:
(1) The expansion phenomenon during heating the Ti-50at%Ni binary mixed powder compacts was observed in the high temperature range above 800°C, and the amount of expansion became smaller with decreasing particle size of Ti powders.
(2) It was recognized that almost all parts of the Ti-50at%Ni specimen sintered at 1050°C for 4 hr showed a TiNi single phase, of which Ni content measured by the atomic absorption analysis was 50.3-50.4at%.
(3) In the internal friction curve for the same specimen mentioned above, there appeared a well-defined peak at about 35°Cfor heating process and another peak at about 20°Cfor cooling process.View full abstractDownload PDF (5499K) -
Teruo Shimizu, Teruhisa Watanabe1981 Volume 28 Issue 4 Pages 131-135
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSSintered porous bearing specimens of bronze having various permeabilities were made using atomized prealloyed powders through compacting, sintering and sizing processes. In order to study relations between the sliding noise and the viscosity of lubricating oil, the specimens were impregnated with base oils having various viscosities, which have no additives yet. Then, to study relations between the sliding noise and the kinds of lubricating oil, the specimens were impregnated with various commercial lubricating oils; for example, spindle oils, mobil oils and turbine oils etc. After the oil-impregnation, the sliding noise was measured with a testing apparatus, which was composed of a driving equipment and a sound analyzing equipment.
The results obtained were as follows; With the decrease of permeability from about 60 x 10-3 darcy to (2-6) × 10-3 darcy and with the increase of viscosity of base oil, the sliding noise in either case decreased gradually. However, the difference in sliding noise among various kinds of commercial lubricating oils could not be recognized clearly, excepting the effect of viscosity. That is, only the effect of viscosity of lubricating oils was thought to be remarkable to the sliding noise.
As a result, the cause will be able to be explained by considering both effects of the permeability of bearings and the viscosity of lubricating oils upon the mechanism of self-lubrication of sintered porous bearings.View full abstractDownload PDF (397K) -
Ryoji Kameda, Masato Sabao, Takao Kawakita, Nobuyuki Isii, Osamu Tsuru ...1981 Volume 28 Issue 4 Pages 136-140
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe authors made a study on anti-corrosion treatment of iron base sintered structural parts, which were collected by the Japan Society of Powder and Powder Metallurgy, to be preserved as memorial samples for more than 100 years in the future. The requirements: 1) The anti-corrosion treatment should be effective for such a long period of time. 2) It should be possible to restore the samples to their original states physically and chemically if necessary during the preservation period.
To find the most practical method of anti-corrosion treatment which suits the above requirements, the authors tried four kinds of anti-corrosion treatment, and obtained the results.
The results: 1) Lacquer coating treatment proved to have the most effective anti-corrosion property among the four methods. 2) The lacquer coating did not cause any change in dimensions of the samples. 3) The lacquer filled the pores of the sample whose apparent density was less than 6.4 g/cm3, but was easily removed by extraction with a solvent such as acetone. 4) As for the sample having 7.0 g/cm3 apparent density, the lacquer did not penetrate through the pores into internal body of the sample even when the sample was dipped in lacquer.
Based upon these results, the authors conclude that lacquer coating treatment is the most practical and suitable method for the above-mentioned purpose.View full abstractDownload PDF (3083K) -
Minoru Akaishi, Nobuo Setaka, Osamu Fukunaga1981 Volume 28 Issue 4 Pages 141-146
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSWC and WC-4.31wt%Co powders were sintered in graphite capsule under conditions of 5.8 GPa and 1300-1800°C. WC powder was compacted at 0.4 and 5.5 GPa and then sintered at 3×10-5 Torr and 1500-1700°C. The maximum hardness and relative density of WC obtained by high pressure and high temperature sintering at 1400-1500°C were 2550 kg/mm2 and 96%, respectively. A remarkable grain growth with its own habit was observed above 1600°C. It is suggested that CO or CO2 gas is captured in the sintered body and these gases are closely related to the grain growth. It is also shown in vacuum sintering that the WC powder compacted at 5.5 GPa is improved in its sinterability compared with that compacted at 0.4 GPa. This is due to the increase in the initial density and the strain introduced to the WC particles.View full abstractDownload PDF (4763K) -
Hisashi Suzuki, Koji Hayashi, Yutaka Kubo, Hideaki Matsubara1981 Volume 28 Issue 4 Pages 147-151
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe two-phase region of vacuum-sintered TiC-Mo2C-Ni alloys with nitrogen was mainly studied in relation to the carbon content. The mechanical properties of the alloys were also studied at low temperatures. The nitrogen was introduced into specimens by use of TiCxNy (Ti-C-N solid solution) powder.
It was found that the width of two-phase region became wider with increasing nitrogen content of the alloy. The phenomenon was closely related to the denitrification of the alloy, where the difference in the amounts of denitrification between high and low carbon alloys enlarged as the nitrogen content increased. It was also found that the nitrogen contained alloys showed excellent mechanical properties with lower nitrogen and higher carbon.View full abstractDownload PDF (2865K) -
Koji Hayashi, Yasuro Taniguchi, Hisashi Suzuki1981 Volume 28 Issue 4 Pages 152-154
Published: June 25, 1981
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSThe determination of the amount of binder and tungsten carbide phases on the fracture surface of WC-Co cemented carbide was attempted by the use of X-ray microanalyzer. It was suggested that the accurate analysis was impossible, because the effects of micro-roughness of the surface on X-ray intensities could hardly be evaluated. The examination by ion microanalyzer gave a similar result.View full abstractDownload PDF (216K)
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