Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 44, Issue 5
Displaying 1-18 of 18 articles from this issue
  • Naoji Nakamura
    1980 Volume 44 Issue 5 Pages 461-467
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Magnetic properties, thermal expansion coefficient α, electrical resistivity ρ and hardness Hv have been studied for the Fe-<about 3%Nb-20%Co-<7%Mo alloys and Fe-<about 7%Ta-20%CO-<7%Mo alloys. All alloys used in this study were water quenched from 1050°C, cold drawn by 97.2% reduction in area and subsequently reheated at 400∼1000°C for less than 5 h. The magnetic properties of Fe-Nb-Co-Mo and Fe-Ta-Co-Mo alloys depend remarkably on the molybdenum concentration, reheating temperature and reheating time. Among these properties, both BrBs and Hc increase particularly with increasing Mo content. α shows a minimum at the composition of 3.5%Mo in the former alloys and a constant value at the composition range of 1∼4%Mo in the latter alloys, respectively. With increasing Mo content in both of these alloy systems, ρ and Hv increase monotonically for the most part. When water quenched, cold drawn and subsequently reheated at 700°C for 30 min, an Fe-about 2%Nb-20%Co-3%Mo alloy exhibits the following values: B8=2.01 T at 8 kA·m−1, Br=1.91 T, BrB8=0.950, Hc=2.08 kA·m−1, \sqrt(BH)maxBrHc=0.910, α=9.5×10−6 at 0∼40°C, ρ=0.274 μΩ·m and Hv=394. Also, an Fe-about 3%Ta-20%Co-3%Mo alloy exhibits: B8=2.05 T, Br=1.95 T, BrB8=0.951, Hc=2.13 kA·m−1, \sqrt(BH)maxBrHc=0.931, α=10.1×10−6, ρ=0.234 μΩ·m and Hv=429.
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  • Shigeru Yonetani, Toshihide Shinohara, Katsuaki Takahashi
    1980 Volume 44 Issue 5 Pages 467-473
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    The residual stresses in the surface layers of carburized and quenched steels are measured in detail by the X-ray diffraction method. The effects of case depths, specimen sizes, and specimen compositions on the generation of residual stress are inquired.
    Residual stress results mainly from the lattice expantion associated with austenite to martensite transformation, and compressive residual stresses in the carburized layer are reduced considerably by the existence of retained austenite remaining near the surface. Distributions of residual stress are correlated with distributions of hardness and retained austenite concentration. The effect of retained austenite on the development of residual stress distribution is quantitatively investigated.
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  • Naohiro Igata, Kazuya Miyahara, Kazuaki Hakomori
    1980 Volume 44 Issue 5 Pages 474-478
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    The radiation anneal hardening of niobium neutron-irradiated to a dose of 3.7×1024 n/m2 (E>1.60×10−13 J) was studied by the internal friction measurement and the tensile test. The niobium wires (dia.: 1.25 mm) used in this study were Marz Grade Niobium (Nb>99.96 wt%, Ta: 0.03 wt%) obtained from Material Research Corporation. The specimens were annealed at 2330 K for 5.4×103 s in vacuum of 1.3×10−5 Pa. Oxygen, nitrogen and carbon contents analyzed chemically after the annealing were 70 wt ppm, 30 wt ppm and trace, respectively. Two peaks of radiation anneal hardening were observed at temperatures of about 470 and 670 K. The internal friction measurement revealed that the 470 K peak of the hardening was mainly attributed to the formation of complex defects, which were radiation induced defects combined with oxygen atoms, and that the 670 K hardening peak was mainly caused by the complex defects formed by the combining of nitrogen atoms and irradiation induced defects. In the longer time annealing, the increase of yield strength by post irradiation annealing increased with increasing concentration of complex defects.
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  • Syotaro Mizobuchi, Shigeki Kano, Kohichi Nakayama, Hideo Atsumo
    1980 Volume 44 Issue 5 Pages 479-486
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Friction and self-welding tests were conducted on several materials used for the contacting and sliding components of a sodium cooled fast breeder reactor. In the present study, the friction and self-welding characteristics of each material were evaluated through measuring the kinetic and breakaway friction coefficients. The influence of oscillating rotation and vertical reciprocating motion on the friction mode was also investigated.
    The results obtained are as follows:
    (1) Colmonoy No. 6, the nickel base hardfacing alloy, indicated the lowest kinetic friction coefficient of all the materials in the present study. Also, Cr3C2/Ni-Cr material prepared by a detonation gun showed the most stable friction behavior.
    (2) The breakaway friction coefficient of each material was dependent upon dwelling time in a sodium environment.
    (3) The friction behavior of Cr3C2/Ni-Cr material was obviously related with the finishing roughness of the friction surface. It was anticipated that nichrome material as the binder of the chrome carbide diffused and exuded to the friction surface by sliding in sodium.
    (4) The friction coefficient in sliding mode of vertical reciprocating was lower than that of oscillating rotation.
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  • Syotaro Mizobuchi, Shigeki Kano, Kohichi Nakayama, Hideo Atsumo
    1980 Volume 44 Issue 5 Pages 486-493
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    The self-welding behavior of various materials was evaluated by measuring the tensile breakaway force of the specimen which had been self-welded in high temperature sodium. Experiments were carried out to investigate the influence of the sodium temperature and the contact stress on the self-welding behavior.
    The results obtained are as follows:
    (1) The self-welding behavior in sodium was recognized to initiate by the diffusion of the principal element through the real contact area.
    (2) Remarkable self-welding behavior was observed for SUS 316 material at 650°C, and for 2(1/4)Cr-1Mo steel at a sodium temperature of 600°C. The self-welding force acting on the real contact area corresponds to the tensile strength of each material.
    (3) Hard chrome plating or hardfacing material showed good self-weld resistance, but the different combinations of SUS 316 with either of these materials were observed to easily cause self-welding.
    (4) The self-weldability of Cr3C2/Ni-Cr material varied with the preparing methods, especially, with the distribution of the binder composition contained in this material.
    (5) A derived equation was proposed to evaluate the self-welding force. It was found that the measured breakaway force was relatively equal to the self-welding force derived from this equation.
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  • Tadashi Osawa, Ichiro Kawakatsu
    1980 Volume 44 Issue 5 Pages 494-500
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    The wettability of a molten tin-lead solder on copper and mild steel plates was investigated in relation to the effects of annealing for the base metals and discussed from the viewpoint of the surface energies on rolling or recrystallization textures of base metals. The wettability was evaluated in terms of the spreading area of solder on the base metals. The spreading test was made by the special designed apparatus, using eutectic tin-lead solder and ZnCl2-NH4Cl aqueous solution flux. The results obtained are summarized as follows.
    (1) The wettability of a tin-lead solder on copper and mild steel plates tended to decrease with increasing annealing temperature of base metals. The spreading area on the copper base metal annealed at 1073 K was approximately 50% of that on the as-rolled copper.
    (2) There was a close relation between the spreading area of solder and the microstructures of base metals. It is suggested that the spreading area of solder depends largely on the surface energies of base metals in the preferential orientation of textures.
    (3) In the spreading process of molten solder it is important for tin of solder to diffuse on the base metal surface prior to spreading of the main solder drop.
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  • Tadashi Igarashi, Yoshinari Amano, Yujiro Kodama
    1980 Volume 44 Issue 5 Pages 501-508
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Ag-In-Sn alloys with various compositions containing total solute elements of 8 at% were oxidized at 873 to 1133 K in air. The depth of the internally oxidized layer, ξ, and the amount of solute elements diffused into the oxidized layer from the unoxidized region, J, were measured in order to investigate the behavior of solute elements and oxygen during internal oxidation. The diffusion coefficient of In, DIn, and Sn, DSn, in the unoxidized region, and that of oxygen, DO, in the internally oxidized layer, and the volume fraction of oxide, fOX, were calculated from J and information about structures of oxides.
    The results obtained are as follows:
    (1) The relation between the depth of the internal oxidation layer and the oxidation time was expressed by a parabolic law at every temperature in the composition range of 0.14≤CSn≤0.53 (CSn=at%Sn/at%(In+Sn)). But the parabolic law was established only at 823 to 1023 K in the alloy of CSn=0.65, and at 973 and 1023 K in the alloy of CSn=0.78.
    (2) The parabolic rate constant, k, increased with CSn up to 0.4 and was reduced with CSn above 0.4.
    (3) DO in the internal oxidation layer was in approximate agreement with the calculated value, DO(cal), by considering the reduction of the Ag phase by oxide dispersion to the diffusion coefficient of oxgen in Ag determined by Eichenauer and Müller. DO was larger than DO(cal) in the alloys containing agglomerated needle-like oxides, while it was reversed in the alloys containing fine oxides.
    (4) The relations among J, DIn, DSn, fOX and the enrichment factor of solute elements in the internal oxidation layer were different in the composition range CSn≤0.4, 0.4<CSn<0.65 and CSn≥0.65. Composition dependence of parabolic rate constant, k, and the tendency of oxide film formation were dominated by fOX determined by the enrichment of solute elements and crystal structures of precipitated oxides.
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  • Toshinobu Yoko, Masahiro Nakano, Tatsuhiko Ejima
    1980 Volume 44 Issue 5 Pages 508-515
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Ultrasonic velocities of molten ZnCl2-MCl (M=Li, Na, K, Cs) binary systems have been measured with a U.S. spectrometer by the double-transducer menthod over the frequency range of 5 to 55 MHz.
    The results obtained are summarized as follows:
    (1) Ultrasonic velocities of molten ZnCl2-MCl binary systems decrease linearly with increasing temperature except the samples of pure ZnCl2 and 6.6 mol%KCl. The dispersion of ultrasonic velocity is observed for the pure molten ZnCl2 below about 730 K, and above this temperature ultrasonic velocity decreases linearly with increasing temperature.
    (2) Thermodynamic quantities such as adiabatic and isothermal compressibilities, heat capacity at constant volume and internal pressure were calculated from the measured velocity data, and their composition dependences were obtained.
    (3) Since the internal pressure indicates the magnitude of cohesive force in the liquid, it can be used as a measure in determing the types of liquid constituents. The fact that the internal pressure of pure molten ZnCl2 is nearly equal to those of organic liquids obviously indicates the existence of polymer or complex ions in the melt.
    (4) Composition dependence of the total structure factor at long wave length limit was determined over the entire composition range. On the basis of the present and previous results, the liquid structures of these binary systems are discussed.
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  • Toshinobu Yoko, Masahiro Nakano, Tatsuhiko Ejima
    1980 Volume 44 Issue 5 Pages 516-524
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Absorption coefficients of ultrasonic waves in the molten ZnCl2-MCl (M=Li, Na, K, Cs) binary systems were measured with a U.S. spectrometer by the double-transducer method over the frequency range of 5 to 55 MHz. Bulk viscosity coefficients of these systems were determined from the measured absorption data.
    The results obtained are summarized as follows:
    (1) Absorption coefficient is greatest in pure ZnCl2 and decreases with increasing content of MCl for all these systems. The absorption coefficient of pure ZnCl2 shows the greatest negative temperature gradient. The temperature dependence of absorption coefficients for the mixtures decreases with increasing MCl content and becomes constant within the experimental error in the composition range of more than 70 mol%MCl for all these systems.
    (2) Bulk viscosity of pure ZnCl2 has an extremely large value and a large negative dependence on temperature. For all the systems, bulk viscosity coefficients on the ZnCl2-rich side decrease markedly with increasing MCl content and the extent of decrease increases in the order of LiCl<NaCl<KCl<CsCl.
    (3) Composition dependences of the apparent activation energies of bulk viscosity, EηB, and the ratio of apparent activation energies of bulk and shear viscosities, EηBEηS were determined. It is found that the ratio EηBEηS is nearly equal to unity on the ZnCl2-rich side except the ZnCl2-CsCl system. This fact may indicate that the mechanism of bulk viscosity is analogous to that of shear viscosity on the ZnCl2-rich side.
    (4) Bulk viscosity coefficients of alkali metal chlorides obtained in the present work are much smaller than those reported by other investigators. Compared with the organic liquids and the calculated values by the two state model combined with the hole theory, it is suggested that the present results are more reasonable than the others.
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  • Tatsuhiko Ejima, Toshinobu Yoko, Tatsuo Kato
    1980 Volume 44 Issue 5 Pages 525-530
    Published: 1980
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Sound velocities and absorption coefficients of ultrasonic waves in a molten ZnCl2-PbCl2 binary system have been measured with a U.S. spectrometer by the double-transducer method over the frequency range of 5 to 55 MHz. The results obtained are summarized as follows:
    (1) Ultrasonic velocities of the molten ZnCl2-PbCl2 binary system decrease linearly with increasing temperature except the lower temperature regions of the samples of pure ZnCl2 and 10.5 mol% PbCl2. The velocity of pure ZnCl2 is lowest and that of pure PbCl2 is highest.
    (2) Thermodynamic quantities such as adiabatic and isothermal compressibilities, heat capacity at constant volume and internal pressure were calculated from the measured velocity data, and their composition dependences were determined.
    (3) Absorption coefficients and bulk viscosity coefficients and both of their negative temperature dependences are greatest in pure ZnCl2 and decrease with increasing content of PbCl2. However, absorption coefficients become constant within the experimental errors in the composition range of more than 50 mol% PbCl2.
    (4) The results obtained in the present work are quite consistent with the previous ones. On the basis of these results, the changes in constituent species with composition of this system are discussed.
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  • Genjiro Mima, Fukuji Inoko, Ken Atagi
    1980 Volume 44 Issue 5 Pages 531-538
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    In order to examine the effects of the screw component of the dislocations parallel to the grain boundary planes on the initiation of fatigue cracks in the boundary affected-regions, aluminum isoaxial bicrystals in which the screw components of the dislocations parallel to the boundary planes in the primary slip systems were varied from 100 to 0% were prodused by a modified Bridgman method. They were tested by the bending fatigue testing machine under constant strain amplitudes of 0.20 and 0.18%, and cyclic frequencies of 30.4 Hz.
    In the component crystals with the screw components larger than about 83% of the dislocations parallel to the boundary planes in the primary slip systems, the initiation of fatigue cracks occurred along the primary slip bands in the boundary affected-regions. On the other hand, the initiation of fatigue cracks was observed not along the primary slip bands in the component crystals with the screw components less than about 45%, but along those in the edges of the specimens or at the hollows formed by the development of the deformation bands.
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  • Fumio Kurosawa, Isamu Taguchi, Ryutaro Matsumoto
    1980 Volume 44 Issue 5 Pages 539-548
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    Phosphides in carbon steel and stainless steel are studied using the non-aqueous electrolytepotentiostatic etching method. The results are summarized as follows.
    (1) Niobium phosphide is found in austenitic stainless steel (SUS 347). The phosphide is fine and eutectic and located in fracture surface of the steel strained at high temperature by Gleeble Test Device. According to the X-ray diffraction analysis of the residues extracted from the steel, the phosphide is identified as Nb8P5 (orthorhombic: a0=2.62 nm, b0=0.947 nm, c=0.346 nm).
    (2) Titanium phosphides are found in continuously cast slab of ferritic stainless steel (SUS 430). The phosphides are needle-, plate-like and dendritic. From the X-ray diffraction analysis of the phosphides, Ti3P(Cr3PN type, orthorhombic), Ti4P3(cubic) and TiP(hexagonal) are found.
    (3) Titanium phosphide is found in carbon steel (0.014%P-0.16%Ti). The phosphide is identified as Ti∼1.7P(orthorhombic) by X-ray diffraction analysis of the extracted residues. Ti/P ratio of the residues is about 1.2. The phosphide precipitates above 873 K and the maximum of the precipitation is found in the temperature range from 973 to 1073 K.
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  • Kazuhiro Yoshihara, Kazuyoshi Nii
    1980 Volume 44 Issue 5 Pages 549-554
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    The change of the surface composition of commercial cold-rolled low carbon Al-killed and rimmed steels was investigated by AES at temperatures between 843 K and 1043 K in vacuum. The segregation behavior of Al-killed steel and that of rimmed steel were almost the same.
    At temperatures below about 950 K, the surface of the steel was covered with the precipitation layer of graphite. At temperatures above about 950 K, graphite layer dissolved into the steel, and sulfur and phosphorus segregated to the surface. As the annealing was prolonged, however, the concentration of sulfur on the surface increased and phosphorus disappeared from the surface. Finally only sulfur occupies surface sites. This change of the surface composition was reversible at the increasing or decreasing temperature.
    Since this steel contains about 0.05 mass% carbon, carbon precipitates as Fe3C below about 996 K in the bulk. However, Fe3C decomposes into iron and carbon on the surface. Then carbon grows as graphite. This steel contains manganese which stabilizes Fe3C. Therefore, the stability range of Fe3C of this steel is widened. Sulfur which segregates on the surface lowers the surface free energy so that the γ phase is stabilized to a lower temperature. Therefore, both manganese in the bulk and sulfur on the surface decrease the precipitation temperature of graphite on the surface from 996 K to about 950 K.
    Sulfur on the surface also decreases the precipitation rate of graphite. In the case of Al-killed steel, however, this effect is canceled by aluminum which accelerates the decomposition of Fe3C.
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  • Kenji Morii, Mitsuo Mera, Yutaka Nakayama
    1980 Volume 44 Issue 5 Pages 555-561
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    Texture development and deformation structures in rolled polycrystalline 70/30 brass have been studied. Deformed structures of grains in the polycrystalline samples are classified roughly into two groups; slip deformation and mechanical twinning followed by shear banding. The texture development is characterized by the following three stages.
    (1) \lesssim40% reduction. Slip or twinning deformation operates depending on the orientations of grains, and leads to the development of the intermediate type texture. (2) 40∼80% reduction. Shear bands are induced in the grains deformed by mechanical twinning. The twined grains having RP\varparallel{112}∼{135} orientations in the intermediate texture rotate toward the RP\varparallel{111} orientation due to the formation of shear bands, and a texture component of {111}⟨uvw⟩ is formed. (3) \gtrsim80% reduction. Two families of shear bands disposed symmetrically with respect to the rolling plane normal are induced in the twined grains, and the shear bands grow markedly. As a result, a texture component of RP\varparallel{011} develops at the expence of the RP\varparallel{111} component. On the other hand, the RP\varparallel{011} component also develops by slip rotation in the grains unfavorable for twinning. It is concluded that the development of a brass type texture may be correlated with the shear bands formation in the twined grains.
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  • Makoto Kumada
    1980 Volume 44 Issue 5 Pages 562-568
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    Intergranular corrosion tests of nonsensitized austenitic stainless steels and rotating-bending fatigue tests of intergranularly pre-corroded stainless steels were carried out to investigate the effects of intergranular corrosion on fatigue strength.
    The following results were obtained.
    (1) Ditches 10 to 20 μm in depth due to intergranular corrosion are found on as-received stainless tubes.
    (2) The depth of intergranular corrosion in strongly oxidizing media increases linearly with exposure time on a full logarithmic scale.
    (3) Fatigue strength decreases with the increase of the depth of intergranular corrosion. Endurance limit of the stainless steels which intergranularly corroded up to the depth of 60 to 120 μm decreases to 68% of that of as-machined stainless steels. As fatigue cracks initiate at the bottom of the ditches, intergranularly corroded stainless steels should be treated as notched materials.
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  • Masayuki Hijikata, Mitsunori Sato
    1980 Volume 44 Issue 5 Pages 569-575
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    Ag-2∼10 at%Zn alloys containing small amounts of several metals such as 1 at%Sn, 1 at%In, 0.5 at%Te, 0.5∼3 at%Cu and 0.5 at%Li were internally oxidized in the air, and at 0.1 and 0.5 MPa oxygen pressures at 1073 and 1123 K. The characteristics of the electrical contact, such as welding adhesion resistance, erosion resistance and contact resistance were investigated.
    (1) Internally oxidized Ag-8∼10Zn-0.5Te, Ag-6Zn-1Sn-0.5Te and Ag-4∼6Zn-1Sn-1In-0.5Te alloys are superior to the electrical contact. (2) The welding adhesion resistance is affected by both the oxide content and the dispersed structure. On the other hand, the erosion resistance is affected by the oxide content, but not by the dispersed structure. (3) The contact resistance increases with increasing oxide content, as well as with the addition of Sn and In.
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  • Mitsunori Sato
    1980 Volume 44 Issue 5 Pages 576-581
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    Silver base alloys containing 11.3Cd, 11.4Cd-0.24Ni, 7.62Zn-0.45Te, 6.13Zn-0.97Sn-0.48Te, and 6.05Zn-1.03Sn-0.99In-0.47Te(at%) were internally oxidized at 1023, 1073 and 1123 K under continuously changed oxygen pressures and in the air. The control of oxide particle size by oxygen pressure has been investigated.
    (1) In order to have the same size of dispersed oxide particles in all the regions of internal oxidation layers, the oxygen pressure P should be controlled with time t as P=K4Pa2t2⁄4Xa4, where K is the velocity constant of internal oxidation at a constant oxygen pressure Pa and Xa is the distance from the surface. The value of K depends on the composition of specimens and the temperature of internal oxidation. (2) The activation energy for internal oxidation is smaller than 92 kJ/mol estimated from the diffusion of oxygen in silver by Eichenauer and Müller. (3) The diffusivity of oxygen in internally oxidized layers and its activation energy are evaluated as being smaller than those in silver.
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  • Takashi Sakaki, Yozyu Simizu, Kazutaka Sakiyama
    1980 Volume 44 Issue 5 Pages 582-587
    Published: 1980
    Released on J-STAGE: April 04, 2008
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    The corrosion behaviour of iron-chromium-nickel alloys was studied by measurements of potentiodynamic polarization curves, the change in natural electrode potential with time, and average penetration. The corrodent used was 48%NaOH solution at temperatures between 140 and 200°C, and the following results were obtained. Anodic dissolution of iron-chromium-nickel alloys in the active state decreased with increasing nickel and chromium content. However, as the potential was raised, nickel in the alloys easily dissolved as the Ni2+ ion at a low potential of Eh=−0.65 V. The passivation current density did not change with the nickel content in the alloys. Addition of nickel to the alloys gave excellent inhibition effects on the dissolution of FeO42− and CrO42− ions at potentials more than +0.6 V. Then, the natural electrode potential of the alloys showed a noble potential with increase in nickel content, but that of the alloys containing 12% nickel remained at low corrosion potentials in the active region. Immersion tests showed that the corrosion resistance of iron-chromium alloys containing 25% chromium or less increased by the addition of nickel, but that the corrosion resistance of the alloy containing about 30% chromium decreased when nickel was added to the alloy.
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