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Volume 28, Issue 1
Displaying 1-10 of 10 articles from this issue
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Kunio Shiobara, Yoshinobu Sawada, Susumu Morioka1964 Volume 28 Issue 1 Pages 1-5
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe anodic behaviour of annealed iron-nickel alloys of nickel content ranging from 0 to 100% was investigated in deaerated sulphuric acid solution at 25°C by means of electrochemical techniques. The semi-conductor type potentiostat was used for polarization measurement. Data concerning the relationship between the composition of alloys and the various properties such as corrosion potential, passivation potential, Flade potential, passivation current density, anodic current density at the passive state and the trans-passive state were presented. It was found that the anodic behaviour of iron-nickel alloys was very much different from that of iron-chromium alloys (previous report), the difference being summarized as follows:
(1) In contrast with iron-chromium alloy, no negative loop was observed in the anodic polarization curves of any of the iron-nickel alloys studied.
(2) Anodic current densities at the passive state, or passivity-maintaining current densities, of the iron-nickel alloys are far greater than that of the iron-chromium alloys, but in the trans-passive region anodic current densities are small for the former compared with that for the latter.
(3) The Flade potential for alloys of nickel content more than 30% appears to be varied depending upon whether the initial potential for the decay trace is set in the passive region or in the trans-passive region. This phenomenon was not observed in the iron-chromium alloys.View full abstractDownload PDF (1564K) -
Kunio Shiobara, Yoshinobu Sawada, Susumu Morioka1964 Volume 28 Issue 1 Pages 6-11
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAnodic polarization behaviours and Flade potentials of pure iron, 40 per cent nickel-iron alloy and 14 per cent chromium-iron alloy in sulphuric acid solutions were studied. The effects of hydrogen ion concentration (pH=−0.3∼4) and sulphate ion concentration (0.2∼1.5 g-ion/L) were examined, keeping concentration of either ion species constant. The results obtained were summarized as follows:
(1) Sulphate ion has a marked effect on the passivation of pure iron. That is, the potential needed for passivation becomes less noble with increasing concentration of sulphate ion up to a definite concentration (0.8 g-ion/L for solution of pH=1).
(2) The effect of sulphate ion which favours the anodic passivation of pure iron becomes less remarkable as the alloying element nickel or chromium in steel increases. Therefore sulphate ion concentration hardly affects the passivation of 40 per cent nickel-iron alloy and 14 per cent chromium-iron alloy.
(3) In the solutions in which sulphate ion concentration has a marked effect on the passivation, the potential needed for passivation does not coincide with the Flade potential. That is, there is a potential range, more noble than Flade potential, in which the passivity of iron and low alloy steels is not maintained.
(4) Effects of sulphate ion concentration on the potential needed for passivation are not recognized in potential decay curve.View full abstractDownload PDF (1577K) -
Sakae Takeuchi, Toshio Honma, Tsuneo Satow1964 Volume 28 Issue 1 Pages 11-15
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe reaction of uranium metal with graphite was studied in the temperature range of 800°∼1100°C. It was found that the reaction rate was parabolic and the activation energy for the reaction was 59 kcal/mole. Marker experiments showed that the growth of carbide film was caused mainly by the migration of carbon. From these results, the rate determining process of the reaction seems to be the diffusion of carbon across the carbide film formed on the metal surface. Hydrocarbon, yielded by hydrolysis of the carbide film, was analysed by gas-chromatographic method, from which results it was confirmed that the film formed in this temperature range was composed of UC only. X-ray diffraction patterns of the carbide films did not show the existence of U2C3 and UC2. From these parabolic rate constants, self-diffusion coefficients of carbon in UC were calculated. The results were extrapolated and found to agree well with the current results obtained by tracer technique.View full abstractDownload PDF (1716K) -
Kyôji Tachikawa, Bin Okai1964 Volume 28 Issue 1 Pages 16-21
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSNb-Zr alloys containing 28 to 57 at% Zr were fabricated into strips 5/100 mm in thickness and also into wires 0.25 mm in diameter. The cold workability of these alloys was improved by high vacuum electron beam melting and by forging at high temperatures. Phase transformation during various heat treatments was studied by X-ray diffraction method and the results agreed with those of Rogers et al. Specimens come to have fine lamellar structures after the eutectoid reaction at 560°C or after the decomposition into two b.c.c. phases at 785°C. The latter heat treatment at 785°C decreases the hardness and facilitates subsequent cold working at room temperature. The heat treatment at 560°C deteriorates the cold workability. The superconducting critical current Ic is increased considerably by cold working and is also sensitive to heat treatments. The decomposition reaction at 785°C and the eutectoid reaction at 560°C are both effective in increasing Ic, whether the specimen is cold worked or not. The intermediate heat treatment at 785°C for about 10 hr between successive cold working is quite profitable because of the improvement of both cold workability and superconducting current capacity.View full abstractDownload PDF (2632K) -
Shigeo Aoki1964 Volume 28 Issue 1 Pages 22-27
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe workability, the effect of the heat treatment on the mechanical properties and the micro-structures, and the corrosion resistance for pressurized water of Zr-1%Mo-1%Cr and Zr-1%Mo-1%Ni alloys which resulted from previous works have been investigated in comparison with Zircaloy 2. The results obtained are summarized as follows. (1) The percent reductions of the alloys drop-forged in the temperature range of 600°∼900°C were nearly same as those of Zircaloy-2. The alloys were cold rolled by 70% without any intermediate annealing. (2) The remarkable hardening occurred in both alloys when they were quenched from β phase. (3) The optimum procedures of the heat treatment to obtain the favourable mechanical properties of Zr-1%Mo-1%Cr and Zr-1%Mo-1%Ni alloys were to temper them at 750°C and 600°C for 100 min respectively, after quenching from 950°C in β phase. (4) The weight gain of Zr-1%Mo-1%Cr alloy over the corrosion period of 500 hr in pure water at 300°C under pressure of 80 kg/cm2 was a little higher than that of Zircaloy-2 but much lower than that of Zr-1%Mo-1%Ni alloy.View full abstractDownload PDF (2892K) -
Yoshimichi Masuda, Eihachiro Tanaka, Sadao Kikuta, Hiromi Tokuno, Masa ...1964 Volume 28 Issue 1 Pages 28-35
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEach process of production techniques of sintered aluminium alloy was studied experimentally by using atomized aluminium powder as starting material. The optimum condition was determined for each process in regarding with the properties of produced alloys.
The results obtained are as following:
(1) The optimum pressure for powder compaction at room temperature was 5 ton/cm2 in taking account of densification and crack formation in compact. At this pressure the powders containing 10∼15 wt% oxide were compacted to a density of 2.2∼2.5 g/cm3, with a compacting factor of 3.0∼3.5.
(2) In extrusion of the hot pressed compact much sounder material of uniform density was produced than in that of the cold compacted powder using the lower extrusion ratio, although the extrusion pressure increased about 10%.
(3) In order to prevent the occurence of defects in the extruded products it is preferable to use of conical die designed to be minimized the shear component in material flow.
(4) For leveling down of the extrusion pressure the using of appropriate lubricant and the higher extrusion speed is advantageous.
As the hot pressed compact containing 11.6 wt% oxide was extruded at 500°C by using a 15:1 ratio and a lubricant of colloidal graphite in extrusion speed of 47 mm/sec, the extrusion pressure became lower than 40 kg/mm2.View full abstractDownload PDF (2834K) -
Yai Shiobara1964 Volume 28 Issue 1 Pages 36-39
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRapid electrographic determination of gold in gold-copper alloys and silver in silver solders was worked out. The method consisted of stripping of alloy constituents into Toyo filter paper moistened with a supporting electrolyte solution and then of measuring the intensity of color developed with colorimetric reagent spectrophotometrically. Suggested electrolyte solution were 0.5 M NH4Cl for gold alloys and 0.01 M KNO3 for silver solders. After electrographic stripping (4 V, 10 mA, 10 sec) of alloy constituents into the filter paper coupled with pressure 2 kg pet 6.25 cm2, the filter paper was treated with 0.5M hydroxylamine sulphate for gold and with 1% potassium chromate for silver to develop the colored pattern to be measured at 600 mμ and 480 mμ, respectively. The method seems to be of special value for rapid and practically nondestructive determination of gold and of silver in their alloys.View full abstractDownload PDF (1131K) -
Nakaaki Oda, Mitsuru Idohara1964 Volume 28 Issue 1 Pages 39-43
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRecent development of the tantalum refining industry made it necessary to determine the trace impurities in the high purity tantalum products. To meet the requirement of increasing sensitivity for the author’s previous intermittent a.c. arc method, a spectrographic d.c. arc method was studied with a medium quartz spectrograph Qu-24. Experiments were carried out to establish the optimum conditions regard to the various factors, such as carrier, arc current, exposure time, internal standard, analytical line pairs etc, yielding a sensitive, simple and rapid method, suited for the practical uses. The method includes converting sample to oxide, mixing with carbon powder which contains two internal standard materials (GeO2, BeO), arcing in a d.c. arc, and photographing spectra with a medium quartz spectrograph. The method can be applied to the analysis of the high purity tantalum products of various forms which could be brought into tantalum oxide, and used to determine the fourteen elements in them at the concentrations greater than 0.01% of Nb, W, 0.003% of Mo, 0.001% of Ti, 0.0005% of Fe, Ca, 0.0003% of Si, Cr, V, Ni, Al, 0.0001% of Mn, Cu, and 0.00003% of Mg, with the precision of about 10%, in terms of the variation coefficient.View full abstractDownload PDF (1117K) -
Noboru Makino, Yasuo Kimura, Masaki Suzuki1964 Volume 28 Issue 1 Pages 43-48
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHomogeneous ZnSb ingot can be prepared, as earlier workers pointed out, by melting the composing elements together in an evacuated silica capsule, cooling the melt in water and subsequently annealing the frozen material at a suitable temperature. According to our observation, a relatively low temperature, 450°C for instance, is preferable as the annealing temperature. A higher temperature, 500°C for example, very frequently causes fine cracks and the thermoelectric properties of ingots are reduced.
In our experiment, ZnSb containing 51 at%Zn exhibits higher thermoelectric power and Hall mobility as well as lower electrical conductivity than those of 50 at%Zn.
Influences of Ag, Cu, In, Sn, Bi, AgI and CuBr additions on thermoelectric properties ZnSb were studied. All these additions give p-type material, and their influences are qualitatively the same, that is to say, decrease thermoelectric power α, and increase electrical conductivity σ. Ag and Cu additions have particularly analogous influences. In both cases, σ increases remarkably, but α decreases comparatively less. These two elements may be added up to 8 wt% in quantity. Being added in such a large amount, Ag gives somewhat larger α2σ than the case of Cu. Sn addition also has an effect similar to that of Ag or Cu addition, but it does not increase α2σ so remarkably as in the case of Ag or Cu. In or Bi addition exhibits rather small effect on properties of ZnSb, i.e. a very small increase of σ. AgI or CuBr addition shows an effect analogous to, but smaller than, that of Ag or Cu. Effect of halogens can hardly be recognized.
The effect of the additions described above may be interpreted to a certain extent as a result of creation of donor or acceptor and vacancies as the result of selective substitution of either Zn or Sb atoms of the added elements.View full abstractDownload PDF (1635K) -
Shiro Sato1964 Volume 28 Issue 1 Pages 48-53
Published: 1964
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRecently, the power stations situated in large cities often encountered with the troubles of severe corrosion of condenser tubes of aluminium brass by polluted cooling water. This paper reports the results of experiments on the individual effect of some factors which are characterizing the polluted water on the corrosion of aluminium brass tubes. The experiments were performed by following two method; (1) the corrosion test on tube specimens in which 3%NaCl solution containing hydrogen sulfide or ammonium ion is circulated through the tubes (2) the corrosion test on sheet specimens using rotating disc corrosion testing apparatus in 3%NaCl solution of various pH containing hydrogen sulfide and in polluted brackish water in which the pH is controlled to be kept in weak alkaline value. Results obtained were as follows; (1) Hydrogen sulfide in order of 1ppm is very active to the corrosion in neutral solution, causing the pitting, but is less active in alkaline solution. (2) Action of ammonium ion in order of 10 ppm or more is also effective to cause pitting, but is not so prominent as that of hydrogen sulfide. (3) Decreasing of pH value from that of clean sea water to that of polluted water with increasing degree of pollution promotes the corrosion without the action of sulfide. (4) Controlling of pH of polluted water in weak alkaline value is effective to inhibit the corrosion but in practice the difficulty by depositing of insoluble calcium carbonate in tubes which will impede the performance of condenser tubes is expected.View full abstractDownload PDF (1591K)
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