Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 57, Issue 7
Displaying 1-18 of 18 articles from this issue
  • Toshitada Shimozaki, Yoshinori Wakamatsu, Masami Onishi
    1993 Volume 57 Issue 7 Pages 729-734
    Published: 1993
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Numerical analysis for the calculation of concentration-distance curves in a binary finite/semi-infinite multi-phase diffusion couple based on the forward finite difference method has been proposed. By use of this method concentration-distance curves in the diffusion couple in which more than three diffusion phase layers are formed can be calculated for various periods of anneal time. This method will be useful to investigate disappearance or growth of the diffusion phase layers in the finite/finite or finite/infinite diffusion couple.
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  • Toshitada Shimozaki, Yoshinori Wakamatsu, Masami Onishi
    1993 Volume 57 Issue 7 Pages 735-741
    Published: 1993
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    When the thickness of film of thin film/semi-infinite diffusion couple is not enough thin, self or impurity diffusivities determined by the so-called thin film solution may include some error and it is supposed that the thicker the film and the smaller the diffusivities, the larger the error.
    In this paper, concentration profiles in the diffusion couple have been calculated numerically by setting the thickness of the film to be 0.01∼0.1 μm and values of the impurity diffusivity to be 10−16∼10−20 m2/s in consideration of the concentration dependence of interdiffusivity. With the aid of this profiles the magnitude of the error of impurity diffusivity has been evaluated.
    Usually, such a small impurity diffusivity has been determined experimentally with the aid of a micro sectioning technique such as ion beam spattering or SIMS. Because the maximum value of the depth of profile determined by these technique is limited to few micron meters at most, the error due to this limitation of apparatus has been mainly studied.
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  • Hideki Hagi
    1993 Volume 57 Issue 7 Pages 742-748
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    In order to obtain the diffusion coefficients of hydrogen in iron free from dislocation and impurity trapping, electrochemical permeation measurements have been done using high purity iron (99.99 mass%Fe), pure iron (99.99 mass%Fe, high substitutional and low interstitial impurity contents), pure iron (99.94 mass%Fe), and commercially pure iron (99.83 mass%Fe) between 278 and 318 K. Though these specimens, in which dislocation densities are (0.6∼4.4)×1011 m−2, have been annealed at high temperatures (973∼1223 K), the diffusion coefficients measured (Da) are influenced by the trapping effect of dislocations.Therefore, the diffusion coefficients free from dislocation trapping (Ddf), and free from dislocation and impurity trapping (DH) have been calculated from Da on the basis of the trapping theory. In the iron specimens of 99.99 mass% purity, the values of DH are nearly equal to those of Ddf. This indicates that Da obtained in the 99.99 mass% purity iron specimens is little influenced by the impurity atoms. The temperature dependence of DH has been determined as follows:
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  • Yoshinobu Tahara, Kensuke Oki
    1993 Volume 57 Issue 7 Pages 749-755
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    Kinetics of isochronal ordering and behavior of vacancies in an FeCo alloy have been investigated with the measurement of temperature derivative of electrical resistivity αR. A part of αR caused by the ordering or disordering, ΔαR, was estimated by eliminating other effects such as magnetic and phonon scattering effect. The data on ΔαR revealed that the homogenious and heterogeneous orderings occur concurrently in the temperature range 650-773 K, whereas only the homogenious ordering occurs above 773 K.
    On the other hand, the kinetic equation of ordering derived in our previous work was expanded, by assuming that the ordering takes place by the migration of vacancies. The variations of ΔαR of the alloy were analysed using the expanded rate equation. It was shown that the two types of homogenious ordering proceed continuously in the range of low temperatures. The one is the ordering due to the quenched-in excess vacancies, about 15% of the equilibrium concentration for the quenched temperature, and the other is due to the thermal ones. The kinetic behavior of ΔαR and vacancies were interpreted satisfactorily by the present expanded rate equation.
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  • Kensuke Kageyama, Manabu Enoki, Teruo Kishi, Kazuhiro Ikuina, Mitsuru ...
    1993 Volume 57 Issue 7 Pages 756-760
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The relationship between the effect of crystallization by anorthite and mechanical properties was investigated by the 4-points bending test and fracture toughness testing (SEPB) in alumina particulate glass composite. PbO-borosilicate glass and CaO-borosilicate glass composite were prepared and crystallized in the interface between glass and alumina or particulate by anorthite and alumina. As crystallized, the bending strength decreased in vacuum because of the initial defects, and increased in air and water because of a decrease of the stress corrosion. On the other hand, the bending strength decreased in all environment where the glass is particulate by anorthite and alumina. By using the AE method, in the noncrystallized specimens, even particulate by anorthite, it was found that the microcrack extended rapidly because of stress corrosion if one microcrack processed. However, if the crystallization occur in the interface between glass and alumina, the crack extension stopped, leading to an increase of the bending strength. Because fracture toughness increased in all environment by the crystallization treatment, it was demonstrated to control the microfracture by crystallization and hence develop the method to obtain the material having the higher reliability in both air and water.
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  • Shuji Ono, Masahiro Saito, Shintaro Matsuo
    1993 Volume 57 Issue 7 Pages 761-766
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The relationship between microstructure and mechanical properties in air of various high Cr cast stainless steels were investigated in order to develop a new marine propeller material 1.5 times (265 MPa) greater in corrosion fatigue strength than nickel aluminum bronze. The results are summarized as follows.
    (1) In order to achieve the target of tensile properties, it is necessary that microstructure of the new steel consists of martensitic, austenitic and ferritic phases.
    (2) Concerning volume of metallographical phases, it is desirable to ensure 5∼30% volume of the austenitic phase and under 25% volume of the ferritic phase.
    (3) Judging from the above-mentioned metallographical phases, the 18%Cr cast stainless steel containing C≤0.04%, Cr: 16∼18%, Ni: 5∼7%, Mo: 1% is almost proper for a new marine propeller material, which satisfies the intended tensile properties.
    The characteristic of this 18%Cr cast stainless steel is that 0.2% proof stress of this steel is half of that of 12%Cr cast martensitic stainless steel, although this steel has almost the same tensile strength as that of 12%Cr cast martensitic stainless steel.
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  • Atsushi Hibino
    1993 Volume 57 Issue 7 Pages 767-773
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The formation rate of Ni-Al intermetallic compounds was measured by dipping Ni wire into Al melt in the temperature range between 973 K and 1373 K, in order to determine the kinetic parameters of combustion synthesis of Ni3Al. The Ni wire and Al powders were put into an alumina crucible and vacuum-sealed in a quartz tube. The tube was kept in an electric furnace to cause the compound formation reaction. The microstructure observation and EDX analysis of the dipped Ni wire were performed. It was found that the compound formation reaction occurred at the interface between the molten Al and the Ni wire, and the cylindrical Ni2Al3 layer was formed in the wire. The thickness of the formed layer depended on the holding time and the dipping temperature. The reaction process had been closely similar to the combustion synthesis process of Ni3Al intermetallic compound. Therefore, the kinetic parameters could be determined by the dipping experiment. The experimental data have been analyzed with a cylindrical model which took into account the diffusion process of Al in the compound layer and chemical reaction on the interface between Ni2Al3 and Ni. The diffusion coefficient, DAl, and the reaction rate constant, kc, were estimated as follows.
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    The calculated curves by using present the kinetic parameters were in satisfactory agreement with the experimental values.
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  • Kazuo Kameda, Katsunori Yamaguchi, Hiroshi Horie, Toshiko Kon
    1993 Volume 57 Issue 7 Pages 774-780
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    A study of thermodynamic properties of the liquid Te-Pb alloys has been carried out by the galvanic cells of
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    The reliable values of E.M.F. were obtained for the alloys.
    Activities of lead at 1210 K show remarkably negative deviations from Raoult’s law in the wide concentration range and abruptly increase from negative to positive around NPb=0.45∼0.65 and show slightly positive deviations on the lead-rich side. Activities of tellurium at 1210 K exhibit significantly negative deviations from Raoult’s law over the whole concentration range. aPb values agree well with the data measured by Moniri and Petot but aTe values differ from those of Predel et al.
    The γPb° and γTe° values are estimated to be 6.4×10−3 and 3.1×10−2 at 1210 K. From the features of α functions of lead for the system, the alloys are not considered as regular solutions. The minimum values of the heat of mixing for the system are −27.2 kJ/mol at about NPb=0.48.
    It is observed that the anomalous behaviors in heats of mixing, ξ function, entropy of mixing and concentration fluctuation at long wave length limit at the composition of PbTe are affected by the stable compound in the liquid state.
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  • Shigeji Taniguchi, Naoyuki Asanuma, Toshio Shibata, Fuhui Wang, Hanyi ...
    1993 Volume 57 Issue 7 Pages 781-789
    Published: 1993
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    Oxidation resistance of TiAl coupons coated with Co-30Cr-4Al and Co-30Cr-4Al-0.2Y (mass%) coatings has been assessed by isothermal oxidation test in a temperature range 1100 to 1400 K and by cyclic oxidation test at 1200 K. The coating, consisting of very fine grains, was prepared by magnetron sputtering with resulting thicknesses of 30∼40 μm. Both the coatings are very effective to suppress the oxidation below 1300 K. This effect is attributable to the formation of α-alumina scales. However, after long oxidation periods, the oxidation manner changes from parabolic to accelerated oxidation. This acceleration is explained in terms of local growth of rutile on the scale. Relatively large voids are formed at the scale/coating interface, within the coating, and the coating/substrate interface. The addition of Y to the coating results in the flat scales with no voids at the scale/coating interface, though the oxidation rate slightly increases and the recrystallization of the coating is delayed.
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  • Akinori Sato, Kenzo Kon, Shigeo Tsujikawa, Yoshihiro Hisamatsu
    1993 Volume 57 Issue 7 Pages 790-796
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The effect of surface orientation on dissolution rate of Alloy 600 with coarse columnar crystals was investigated by potentiostatic etching in the active region in H2SO4-NH4SCN and H2SO4-NaCl solutions. {100}∼{110} planes and {110}∼{111} planes were prepared by cutting at 90° and 45° to ⟨100⟩ growth direction of the columnar crystals. Flat surfaces were formed on grains after etching. As the depth of dissolution from the initial surface increased linearly with the etching time, the dissolution rate was treated as constant on every grain. The dissolution rate also changed with the etching potentials and solutions. The orders of the dissolution rate on the {hkl} surface, V⟨hkl⟩, were as follows: V⟨100⟩<V⟨110⟩\fallingdotseqV⟨111⟩ at −0.1 V (vs. SCE), V⟨100⟩<V⟨111⟩<V⟨110⟩ at +0.1 V in 0.5 kmol·m−3-H2SO4+2.5 mol·m−3-NH4SCN solution and V⟨111⟩\fallingdotseqV⟨100⟩<V⟨110⟩ at 0 V in 2.5 kmol·m−3-H2SO4+0.5 kmol·m−3-NaCl solution. Residual planes in each condition were determined from these dissolution rate ratios.
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  • Hirofumi Miyahara, Nobuyuki Mori, Keisaku \={O}gi
    1993 Volume 57 Issue 7 Pages 797-803
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The effect of electroless copper plating 0.08 to 4.5 μm thick on the wettability of Al2O3 substrate and fiber preform by molten aluminum were investigated with the sessile drop method in a vacuum of 2×10−3 Pa at temperatures from 973 to 1173 K.
    The contact angle of molten aluminum on Al2O3 substrate decreased from 113° to 92° as the temperature rose from 973 to 1173 K. The electroless copper plating on Al2O3 reduced the contact angle to less than 40° when the thickness of plating was larger than 0.3 μm at 973 K. The apparent contact angles between molten aluminum and 15 volume%Al2O3 fiber preform were about 140°∼145° at 973∼1073 K. Electroless copper plating reduced the angle, and molten aluminum was spontaneously infiltrated into preform when the thickness of plating was larger than 0.5 μm at 973 K, 1.4 μm at 1073 K. The thin copper plating could not improve the wettability, because copper deposits on Al2O3 coagulated due to the surface energy and the Al2O3 surface was partially exposed at high temperatures. The coagulation became more remarkable as temperature rose. By these phenomena, the molten Al drop, which once spread on the copper plated Al2O3 substrate, moved back towards the receding contact angle. The interaction between the coated copper and the molten aluminum was metallographically investigated.
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  • Yoshihito Kawamura, Akihisa Inoue, Tsuyoshi Masumoto
    1993 Volume 57 Issue 7 Pages 804-812
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    Al-Ni-Ln (Ln: lanthanide metal) amorphous alloys with high strength have attracted attention as a structural light metal. The practical use of the amorphous alloys requires the development of a consolidation technique into a bulky form with full density. The effects of extrusion temperature, reduction in cross-sectional area (RA) and construction of billet on the degree of consolidation and structure of extruded bulks were examined for Al85Ni10Mm5 (Mm: mischmetal) amorphous powders produced by high pressure gas atomization. In the case of an ordinary billet, the resulting bulks consist of crystalline phases with full density because of the difficulty of the suppression of crystallization during extrusion. On the other hand, by using a billet with an appropriate core, an amorphous bulk with full density was obtained. The high degree of consolidation in the case of the core billet is presumably because of the generation of a high pressure leading to full density even at a small RA and the effective utilization of large shear stress generating at the outside part of the billet. The compressive strength of the Al85Ni10Mm5 amorphous bulk produced by the use of the core billet reaches 900 MPa which is the same as the tensile fracture strength of the melt-spun Al85Ni10Mm5 amorphous ribbon.
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  • Masao Komai, Yuji Yamasaki, Ken-ichi Takagi
    1993 Volume 57 Issue 7 Pages 813-820
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    Effects of Cr on the mechanical properties, corrosion and wear resistances, and phase formation of Mo2NiB2 base hard alloys were studied using the alloys whose compositions were Ni-6 mass%B-58.6 mass%Mo-(0-15)mass%Cr. The alloys consist of a Mo2NiB2 type ternary boride as a hard phase and a nickel base binder alloyed with Cr and Mo, both of which are formed by reaction boronizing sintering.
    The transverse-rupture strength (TRS) of the alloys depended strongly on the microstructure, which varied significantly with Cr content. The maximum TRS of 2.3 GPa and a hardness of 87 RA was obtained at 10 mass%Cr content. The structure of the boride phase changes from the orthorhombic M3B2 (M: Metal) to the tetragonal M3B2 with increasing Cr content. The highest TRS value obtained at 10 mass%Cr was attributed to the formation of fine M3B2 with tetragonal structure.
    The corrosion resistance of the alloys in a 10 mass%HF and a 10 mass%HCl solutions was superior to the corrosion resistance of a WC-10 mass%Co cemented carbide, PM high speed steel, stainless steels such as JIS SUS405, 440C, 316L and 304 and a tool steel JIS SKD11, but close to that of Hastelloy C. Moreover, in a 10 mass%HNO3 solution, Cr-containing alloys also showed good corrosion resistance with increasing Cr content.
    Abrasive and sliding wear resistances of the alloys were better than those of PM high speed steel, stainless steels and SKD11, and comparable to that of cemented carbide.
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  • Kenji Tokuda, Koji Hayashi
    1993 Volume 57 Issue 7 Pages 821-826
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    The pressureless sintering densification characteristic of NiAl+Ni mixed powder, the composition of which was mainly in Ni3Al intermetallic compound and Ni+Ni3Al two phase alloy, was investigated. It was found that completely densified compacts of Ni3Al intermetallic compound and Ni+Ni3Al alloy with a large amount of Ni3Al could be obtained by controlling the powder particle size and the sintering condition, though the densification of Ni-rich (82∼100 at%Ni) sintered compacts was incomplete. These results were thought to be explained by the authors’ theory of “Equilibrium gas pressure”, i.e., “The densification in the final stage of solid phase sintering is affected by whether the equilibrium pressure of the gas (CO in this case) generated by the reduction of oxide is higher or lower than the surface stress (the driving force of the shrinkage) of the closed pores”, which have been reported in the previous papers. The bending strength and hardness of the completely densified Ni3Al intermetallic compound were 1.3 GPa and 330 HV, respectively, and those of Ni+Ni3Al alloy were 2.9 GPa and 310 HV, respectively.
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  • Yukio Inokuti, Kazuhiro Suzuki, Yasuhiro Kobayashi
    1993 Volume 57 Issue 7 Pages 827-831
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    As a means for improving the iron loss in grain oriented silicon steel sheets, a TiN ceramic film was formed by a CVD method on the polished silicon steel sheet. The following results were obtained.
    (1) The TiN ceramic film moderately increased the magnetic flux density B8 (T) of the silicon steel sheet by 0.009-0.012 T, while the iron loss W17⁄50 (W/kg) was dramatically improved by 0.11-0.23 W/kg. This improvement in iron loss is more marked in silicon steel sheet with a higher magnetic flux density. For example, a silicon steel sheet with B8=1.93 T and W17⁄50=0.89 W/kg after magnetic domain refinements manifested an ultra-low iron loss of 0.57 W/kg, which represents to a 36% improvement in iron loss.
    (2) The difference in iron loss when the TiN film was formed on a polished silicon steel sheet by the thermal CVD method was 0.01-0.03 W/kg greater than that when plasma CVD was used.
    (3) In a comparison of the results of the CVD and PVD methods, a similar difference was obtained with the PVD method (HCD), which produced an iron loss 0.01-0.05 W/kg greater than that with the CVD method.
    (4) No appreciable difference among TiN silicon steel sheets was apparent in magnetostriction or magnetic domains, and it is suspected that these differences in the improvement of iron loss (ΔW) were due to the coating conditions used for CVD or PVD, or to a slight difference in the properties of the TiN film by each method.
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  • Hiroshi Sato, Takateru Umeda
    1993 Volume 57 Issue 7 Pages 832-839
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    Crystalline phases and amorphous formation regions for the pseudo-ternary BaO-Fe2O3-B2O3 system were investigated using melt spinning and water quenching techniques. Specimens were heat treated, examined to determine the composition and temperature ranges where the BaO·6Fe2O3 precipitated, and the relationship between crystalline phases and magnetic properties was discussed.
    All as-quenched specimens produced by melt spinning with a composition range of less than 70 mol%Fe2O3 and less than 70 mol%BaO were in an amorphous state, and amorphous formation region in the case of water quenching was restricted to the composition range of less than 40 mol%Fe2O3 and more than 20 mol%B2O3.
    In the pseudo-ternary BaO-Fe2O3-B2O3 system, the composition regions were classified according to the kind of precipitated phases. In each region, the relationship between the heat treatment temperature and the relative amount of the precipitated phases was clarified. The amount of BaO·6Fe2O3 in the composition region between lines P (the tie-line between BaO·6Fe2O3 and BaO·B2O3) and Q (the tie-line between BaO·6Fe2O3-BaO·Fe2O3 and BaO·B2O3-3BaO·B2O3 eutectics) increased as the BaO/Fe2O3 ratio in a sample became closer to 1/6. In this region, the composition ranges were determined where fine BaO·6Fe2O3 particles of high coercive force (higher than 240 kA/m (3 kOe)) precipitated from the amorphous phases after heating. In the composition region between lines Q and R (the tie-line between BaO·Fe2O3 and 3BaO·B2O3), some ribbon specimens showed the maximum coercive force of 488 kA/m (6.1 kOe), but they contained very fine BaO·6Fe2O3 particles which indicated superparamagnetism.
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  • Yi Tan, Tetsumori Shinoda, Yoshinao Mishima, Tomoo Suzuki
    1993 Volume 57 Issue 7 Pages 840-847
    Published: 1993
    Released on J-STAGE: April 04, 2008
    JOURNAL FREE ACCESS
    It is shown that the stoichiometry of the ternary β phase in the Ni-Fe-Al system splits into two through the measurement on hardness distribution and through careful examination on the available lattice parameter data. The first stoichiometry lies on the compositions connecting NiAl and FeAl, whereas the second on those connecting NiAl and the Fe corner. The former is attributed to the situation where all the Al atoms preferentially occupy one of the two sublattices so that the compositions are expressed strictly as (Ni, Fe)Al. The latter case, on the other hand, is the situation where Fe atoms are evenly distributed among the two sublattice sites. The lattice parameter of the β phase exhibits a negative deviation from the Vegard’s law in the vicinity of the first stoichiometry but it shifts into a positive deviation as the aluminum concentration decreases. The reason for the negative deviation would be due to the increasing stability of the β phase, while that for the positive deviation to the effect of miscibility gap exsisting in the Ni-Al-Fe ternary bcc phase. There found three types of concentration dependence of solid solution hardening or defect hardening in the ternary β phase, for which a rigorous explanation cannot be made by any of the conventional theoretical treatments.
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  • Seishi Abe, Katsumi Mochizuki, Katashi Masumoto
    1993 Volume 57 Issue 7 Pages 848-851
    Published: 1993
    Released on J-STAGE: April 04, 2008
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    Lead calchogenide compound semiconductors such as PbS are expected to be suitable materials for the tunable laser diodes, which lase at mid-infrared region between 3 and 4×10−6 m. In this study, the solubility range and the lattice constant of a new quaternary solid solution semiconductor Pb1−x(Ca1−ySry)xS are investigated. The solubility range was determined at 1273, 1123 and 973 K. The lattice constant is evaluated as a function of the compositions x and y. For the fabrication of the double-heterostructure laser, it was known that the suitable compositions x and y in Pb1−x(Ca1−ySry)xS as a cladding layer, which is lattice match to PbS as an active layer, can be easily chosen in the solubility range.
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