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Volume 16, Issue 3
Displaying 1-5 of 5 articles from this issue
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[in Japanese]1969 Volume 16 Issue 3 Pages 127-133
Published: July 25, 1969
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSDownload PDF (524K) -
Tetsuo Sakai, Zenshiro Hara1969 Volume 16 Issue 3 Pages 134-139
Published: July 25, 1969
Released on J-STAGE: February 08, 2011
JOURNAL FREE ACCESSIron powder compacts under pressure were sintered by passing an electric current through the electrodes attached on the side of the compact. Apparent density and hardness of the sintered compacts increased with increasing electric current, secondary voltage and compacting pressure. But the tensile strength of the samples, which were fed with excessive electric power and partially melted, were lower than that of the uniformly sintered samples.View full abstractDownload PDF (1707K) -
[in Japanese], [in Japanese]1969 Volume 16 Issue 3 Pages 140-144
Published: July 25, 1969
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn order to study the densification behaviors, several tungsten powders were hot-pressed in vacuum at 1100-1300°C for 10 min under the pressure of 750-875kg/cm2. The density of the sintered specimens was 60-82% of the theoretical value, indicating that they are still in the initial stage of densification. Without additives, higher density is achieved with fine powders, but the density is not a simple function of the average particle size. In mixed powders, different densification behaviors were observed at lower temperatures and the densification is not affected significantly by the powder parameters. Summarizing, important factors in densification are powder, temperature and pressure in the order stated.View full abstractDownload PDF (1869K) -
Hiroshi Ito, Masaru Furusawa1969 Volume 16 Issue 3 Pages 145-149
Published: July 25, 1969
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIn an attempt to improve the oxidation resistivity of sintered tungsten compacts, effects of chromium content on the oxidation resistivity, transverse rupture strength and hardness have been studied in the sintering activated by paladium.
1) The best oxidation resistivity was obtained with alloys containing 20 wt% chromium, and weight gain at 1200°C was 5mg/cm2 for this composition.
2) Transverse rupture strength and hardness decreased with increasing chromium content.View full abstractDownload PDF (3040K) -
Azusa Majima, Yoji Awano, Hiroshi Hamamoto, Takashi Kimura1969 Volume 16 Issue 3 Pages 150-156
Published: July 25, 1969
Released on J-STAGE: May 22, 2009
JOURNAL FREE ACCESSIn the conventional way for increasing ductility of iron-copper compacts, emphasis has been layed on obtaining their homogeneous structures by sintering above the melting point of copper. Also in our experiments which were carried out according to the above method, both the tensile strength and the elongation of sintered iron-copper compacts increased with compacting and repressing pressures. But it was observed that the elongation decreased with rising sintering temperature and extending sintering time, while the tensile strength increased.
The authors assumed that both the elongation and the strength might increase by means of two-stage sintering, thus effectuating tight bonding of iron particles in the primary sintering under the melting point of copper and subsequent partial diffusion of copper into the iron skeleton above the melting point of copper. And it has been proved experimentally that the elongation of sintered iron-copper compacts was improved by this process without significant decrease in the tensile strength. The results were confirmed with the aid of photomicrography and electron microanalyser analysis.View full abstractDownload PDF (2118K)
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