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Volume 23, Issue 4
Displaying 1-6 of 6 articles from this issue
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Satoshi KAWAI1973 Volume 23 Issue 4 Pages 143-150
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSCobalt is electro-deposited on the anodic oxide cating of aluminum in the sulfate solution with an alternating current. Cobalt metal, electro-deposited in regularly arranged columnar pores of the anodic surface of aluminum, shows strong magnetic anisotropy and can be used as a memory material for magnetic devices. The results of the present study are as follows:
(1) Electron microscopic and X-ray studies revealed that fine granular metals of α-cobalt existed in columnar micro-pores of the anodic coating.
(2) Strong magnetic anisotropy perpendicular to the surface was observed in films which were anodized in the sulfric acid, the oxalic acid and the sodium bisulfate solution. However, films anodized in the chromic acid and the sodium hydroxide solution showed weak anisotropy. Further, it was found that the anisotropy of films anodized in the phosphoric acid was stronger along the parallel direction than along the perpendicular direction.
(3) Coercive forces of anodic oxide films formed in the sulfuric acid depended on the elctrolytic voltage and varied between 1000 and 1600Oe. Residual magnetization increased with the amount of deposited metals.View full abstractDownload PDF (1081K) -
Satoshi KAWAI1973 Volume 23 Issue 4 Pages 151-156
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSBy using various sulfate solutions of Co and Ni, Co-Ni alloys were electro-deposited on oxide coating of aluminum, anodized in sulfuric acid. Co-Ni layers which precipitated in micro-pores of the oxide films showed magnetic anisotropy in vertical and horizontal directions. The present study resulted in the following observation:
(1) X-ray analyses revealed that the h. c. p. α-structure of Co changed to the f. c. c. β-structure when the Ni content exceeded about 50%.
(2) The coercive force along the direction perpendicular to the surface varied between 750Oe of pure Ni and 1100Oe of pure Co and had the minimum value of 700Oe at the Co content of about 50%. However, the coercive force along the horizontal direction was the maximum, 1150Oe, nearly at the same Co content.
(3) The composition dependence of the magnetic remanence was similar to that of the coercive force. The maximum value of the magnetic remanence was about 600 Gauss. It was considered that the anisotropy along the lateral direction was caused by the deposit crystals with the lamellar structures.View full abstractDownload PDF (681K) -
Takeshi INOUE, Masao KATO, Kenjiro GOTO, Goro ITO, Yoshihiko SHIMIZU1973 Volume 23 Issue 4 Pages 157-163
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSFollowing a previous report on effects of pH and oxidizing agents on pitting of aluminum, the present study was conducted to investigate influence of concentration of anion inhibitors such as sulfate, silicate and phosphate and of free chlorine on initiation and propagation of pitting. Testing solutions were prepared by adding 5ppm of chloride, 0.1-50ppm of the inhibitor and 0.5-5ppm of free chlorine to deionized water. The pH of the solutions were adjusted to 6.0-7.0 with dilute hydrochloric acid or sodium hydroxide solutions. Corrosion tests were conducted in stagnant water at 35°C for 100hours. The results obtained are as follows:
(1) The increase of free chlorine concentration had more effective influence on the initiation of pitting than on the propagation, while the incrcase of concentration of every inhibitor had a considerable effect on the propagation of pitting.
(2) Logarithm of the average pit depth was linearly related to that of the concentration of each inhibitor. However, the average pit depth had no relation to the free chlorine concentration.
(3) The distribution curve of the number of pits versus the pit depth had a long tail in the side of the deeper pit. This fact suggested that the distribution was expressed in an exponential type function.
(4) The effects of the concentration of a particular inhibitor on the propagation of pitting were discussed by applying the extreme value analysis, proposed by Aziz, to the maximum pit depth data.View full abstractDownload PDF (721K) -
Kenjiro GOTO, Yoshihiko SHIMIZU, Goro ITO1973 Volume 23 Issue 4 Pages 164-172
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSA pitting corrosion characteristic of pure aluminum in supply water, artificially synthetized from Ca2+, Mg2+, HCO-3, Cl-, SO42-, SiO32- and free chrorine, was studied. Experimental results showed that free chlorine, SiO32- and Ca2+ were harmful in producing pitting of aluminum in water. However, effects of HCO3-, Mg2+ and Cl- on pitting were hardly recognized. Interaction among the above constituent species was almost absent in pitting corrosion of aluminum. The results of the present study were analyzed by applying the statistical theory of the extreme value, proposed by P. M. Aziz.View full abstractDownload PDF (1805K) -
Shiro SATO1973 Volume 23 Issue 4 Pages 173-180
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe process of plastic deformation during bending and the method of bending tests specified by JIS were discussed with experiments of simple bending tests (Fig. 1), performed for aluminum alloy sheets, 7NO1-T6 with thickness of 10mm and 5083-0 with thickness of 16mm. The principal results obtained were as follows:
(1) The relation between the maximum bending strain and the bending angle were not affected bythe variation of supporting distance.
(2) The bending strain at the middle point of a test piece reached the maximum value at a bend angle near 100 degrees and kept its value over 100 degrees. Therefore, it seems that cracks would develop at a bend angle less than 100 degrees if they should occur.
(3) Test pieces did not always conform to the radius of the mandrel and the internal radius of test pieces were much less than that of the mandrel. Therefore, even if the ratio of the mandrel radius to the test piece thickness. R/T, and the bending angle were kept constant, the maximum bending strain depended on the tested materials.
(4) However, for an identical material, almost the same relation between the maximum bending strain and the bending angle was observed when R/T was kept constant.
(5) When the spcification required a bend angle of 180degrees, the test was started by the simple bending method (Fig. 1) and followed by a procedure ofpressing the arms ofatest piece to get 180degree bending, as shown in Fig. 2. With this method, the amount of the increase of the maximum bending strain depended on the amount of the bend angle produced by the first stage bending and the variation of the relative position of the test piece and the distance piece at the second stage bending.View full abstractDownload PDF (746K) -
Shotaro MOROZUMI1973 Volume 23 Issue 4 Pages 181-187
Published: April 30, 1973
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (1325K)
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