TANSO

Fracture Toughness of Reactor Grade Graphites

1st Report: Fracture Toughness at Room Temperature

Hideo Awaji, Sennosuke Sato

1979 Volume 1979 Issue 96 Pages 2-7
Published: January 25, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.7209/tanso.1979.2

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The disk-test in which a circular specimen with an internal crack is subjected to diametral compression is used to investigate fracture toughness of reactor grade graphites.The stress intensity factor of the mode I in the disk-test is given in the convenient form considering the Hertzian contact by compressive anvils.As specimens, all the 9 kinds of isotropically molded and anisotropically extruded graphites are measured at room temperature.Also, the equivalent crack lengths are deduced and compared with actual defects in the microscopic structures.

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Fracture Toughness of Reactor Grade Graphites

2nd Report: Fracture Toughness at Elevated Temperature

Sennosuke Sato, Hideo Awaji

1979 Volume 1979 Issue 96 Pages 8-14
Published: January 25, 1979
Released on J-STAGE: June 28, 2010

DOIhttps://doi.org/10.7209/tanso.1979.8

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By means of the disk-test, fracture toughness values of reactor grade graphites are measured at high temperature up to 2600°C. As specimens, four kinds of isotropically molded and anisotropically extruded graphites are measured.The results show that the fracturetoughness values are found to increase as temperature is increased.At 2000°C, for instance, thevalues were about 1.5 times larger than those of the room temperature.The temperature dependencies oftensile properties, Young's moduli, equivalent crack lengths and energy release ratios have been discussed.

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On the ζ-Potential of Carbon Black Particlesin Alkaline Aqueous Solution

Tetsuo Murata, Yoshiharu Matsuda, Hiroshi Imagawa

1979 Volume 1979 Issue 96 Pages 15-19
Published: January 25, 1979
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.7209/tanso.1979.15

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The ζ-potential was measured in aqueous alkaline solutions as a part of studies of the dispersion of carbon black particles, and its origin has been discussed.The growth of the ζ-potential is connectedwith OH^- anion as a potential-determining ion, surface acidic groups (-COOH, -OH) dissociated on the particles, and quinone group reacted with cations.Also, the influence of the slipping plane in electric double layer was large on the ζ-potential.The interactions between alkali metal cations and the surface of the particles were compared with that of alkaline earth metal cations.The | ζ | -potential of the carbon black particles was greater value in aqueous solutions of alkali metal hydroxides than in that of alkaline earth metal hydroxides.The order of the influence of the cations on the ζ-potential was as following:
Cs⁺>K⁺>Na⁺>Li⁺in alkali metal cations, and
Ca²⁺>Sr²⁺>Ba²⁺ in alkaline earth metal cations.
This order of the alkali metal cations was quite contrary to that of the graphite particles in a previous study.This difference would be related to the adsorbability of the cations, the amounts of the functional groups on the surface of the particles and the free energy of hydration of the cations to both samples.

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[title in Japanese]

[in Japanese]

1979 Volume 1979 Issue 96 Pages 20-32
Published: January 25, 1979
Released on J-STAGE: March 01, 2011

DOIhttps://doi.org/10.7209/tanso.1979.20

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