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Volume 56, Issue 4
Displaying 1-18 of 18 articles from this issue
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Hiroshi Haji, Kousuke Miyoshi, Toshiaki Morita, Hideharu Nakashima, Hi ...1992 Volume 56 Issue 4 Pages 355-360
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to develop a microstructure observing technique for bonded interfaces, which is important in the IC industry, thin films of wire-bonded Au-Al samples were prepared by ion milling and microtome techniques and observed by transmission electron microscopy. The effect of heating on the microstructure and residual stress was also investigated by electron and X-ray diffraction. The results obtained are as follows.
(1) In the films prepared with a microtome no amorphous phase is observed, whereas in the films prepared by ion milling a large part of the intermetallic compound formed on the interface is in the amorphous state. (2) The Al2Au5 phase grows predominantly among the five intermetallic compounds which can be formed on the interface. (3) Voids are produced by heating along the Au-Al2Au5 boundary. (4) A larger compressive residual stress is produced after heating on the Au side than on the Al side.
From these results, a suitable technique for microstructure observation of the interface and the deterioration mechanism of the bonded interface are discussed.View full abstractDownload PDF (1604K) -
Fukuji Inoko, Keizo Kashihara1992 Volume 56 Issue 4 Pages 361-370
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSRecrystallization along deformation bands in aluminum single crystals with Schmid factor of 0.5, which were deformed in tension to the strain of 30%, was examined with special reference to the relationship between the orientations of recrystallized grains and the estimation for the activated slip systems. Although a few recrystallized grains are formed due to the strain induced boundary migration (SIBM), most of the recrystallized grains have the orientations obtained by the rotation of deformed matrix about the axis normal to one of the four {111} planes. The estimation for the probability of the choice of rotation axis on each recrystallized grain agrees comparatively well with the actual results obtained.View full abstractDownload PDF (2060K) -
Fukuji Inoko, Keizo Kashihara1992 Volume 56 Issue 4 Pages 371-377
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to investigate the distributions of recrystallized grains in the surface and inner layers, recrystallized grains in 99.99 mass% aluminum single crystals with the Schmid factor of 0.5 deformed in tension to the strain of 30% were examined. After annealing under certain conditions recrystallized grains are preferentially formed along the deformation bands near the surface layer and grown into the inner layer along the corresponding deformation bands. Most of the orientations of the recrystallized grains are obtained by the rotation of the deformed matrix about the axis normal to one of the four {111} planes. Less than 10% of the total recrystallzied grains are formed due to the strain induced boundary migration. The reason why the formation of recrystallized grains along the deformation bands in the surface layer occurs at the earlier stage than that in the inner layers should not be the temperature difference between the surface and the inner layer, but the existence of the free surface.View full abstractDownload PDF (1190K) -
Shigeo Sato, Fujio Urushihara, Tomoo Suzuki1992 Volume 56 Issue 4 Pages 378-383
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPhase decomposition and metastable miscibility gap in the Fe-Mo-Ni ternary system were investigated by means of transmission electron microscopy, X-ray diffraction and hardness measurement. The results obtained are as follows:
(1) At 773 K, spinodal decomposition occurs in Fe-16 at%Mo-Ni alloys containing Ni more than 4 at%, in Fe-14 at%Mo-Ni alloys containing Ni more than 8 at% and in Fe-12 at%Mo-12 at%Ni alloy.
(2) At 773 K, a plate-shaped zone appears by the nucleation and growth mechanism in Fe-16 at%Mo-Ni alloys containing 0∼2 at%Ni, Fe-14 at%Mo-Ni alloys containing 2∼6 at%Ni, Fe-12 at%Mo-Ni alloys containing 4∼10 at%Ni and Fe-10 at%Mo-10 at%Ni alloy.
(3) The coherent spinodal temperatures of Fe-12 at%Mo-8 at%Ni, Fe-14 at%Mo-8 at%Ni and Fe-16 at%Mo-8 at%Ni alloys are estimated at 740, 790 and 845 K, respectively.
(4) The coherent spinodal temperature of Fe-Mo binary system is raised about 15 K by the addition of 1 at%Ni.
(5) The plate-shaped zone is formed in the temperature range of about 50∼100 K above the spinodal temperature.View full abstractDownload PDF (1774K) -
Spinodal Decomposition of High Nickel Fe-Mo-Ni Ternary Alloy and Precipitation Region of Ni3Mo PhaseShigeo Sato, Fujio Urushihara, Tomoo Suzuki1992 Volume 56 Issue 4 Pages 384-389
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSPhase decomposition and precipitation of the Ni3Mo phase in high Ni Fe-Mo-Ni ternary alloys were investigated by means of transmission electron microscopy and hardness measurement. The results obtained are as follows: In Fe-14 at%Mo-14 at%Ni alloy, a modulated structure can be seen at the aging temperature below 823 K. At 773 K, a Mo-rich zone of the modulated structure changes into a bcc η phase with the progress of decomposition. A stable λ phase ((Fe, Ni)2 Mo) appears after precipitating the η phase. This aging process is analogous to the case of the Fe-20at%Mo alloy. At 673 K, the λ phase is directly formed in the interface of the Mo-rich zone and the Mo-poor zone. At 623 K, Ni3Mo phase precipitates in the Mo-poor zone of the modulated structure.
The Ni3Mo phase is observed in Fe-2 at%Mo-Ni alloys containing more than 16 at%Ni and in Fe-14 at%Mo-Ni alloys containing more than 10 at%Ni. The precipitation region of the Ni3Mo phase at 623 K has been obtained as shown in Fig. 10.View full abstractDownload PDF (1740K) -
Fuyuki Yoshida, Norio Matsuda, Keisuke Matsuura1992 Volume 56 Issue 4 Pages 390-398
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSHigh temperature tensile tests and creep tests were carried out for two kinds of P/M Al-8 mass%Fe alloy specimens with different grain sizes. The stress and temperature dependences of minimum creep rate and the effect of grain size on them were examined, and the creep curves were analyzed by using the θ-projection method.
The minimum creep rate increased rapidly with stress in the high stress range above a critical stress. The critical stress did not depend on the test temperature and depended on the heat treatment of specimen. It was nearly equal to the room temperature yield stress of the specimen which was taken to correspond to the Orowan stress. The activation energy of the minimum creep rate was nearly equal to that of the self diffusion of Al, Qd, in the high stress range above the critical stress. It was, however, higher than the Qd in the lower stress range than the critical stress, showing that the creep deformation in the low stress range was affected by the diffusion creep or grain boundary sliding mechanism while the dislocation creep was still dominant.
The creep curves were well described by the θ-projection method. The θ parameters characterizing each creep curve showed generally different stress and temperature dependences below and above the critical stress. For example, strain parameter θ1 for primary creep was nearly constant independent of the temperature and stress below the critical stress, while it increased with stress above the critical stress. The activation energy of rate parameter θ2 for primary creep was about equal to that of the self diffusion of Al, Qd, above the critical stress, while it was lower than the Qd and rather closer to that of the grain boundary diffusion below the critical stress.View full abstractDownload PDF (1491K) -
Koichi Matsumoto, Hiroo Numata, Izumi Ohno, Shiro Haruyama1992 Volume 56 Issue 4 Pages 399-405
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSElectrochemical behavior of Ti3+ in LiCl-KCl eutectic melt at 773 K has been studied with electrochemical polarization technique. The cathodic polarization curves reveal three current peaks at −0.7∼0.8, −1.2 and −1.5 V, two of which are attributed to the reduction of Ti3+/Ti2+(−1.2 V) and Ti2+/Ti(−1.5 V) redox systems. Cyclic voltammograms for reduction of Ti3+ are characteristics of quasi-reversible redox reaction while those for oxidation of Ti2+ show rather complicated phenomenon in relation with the disproportionation reaction as follows:
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The black powdery electrodeposit was obtained by the long time electrolysis and X-ray diffraction analysis shows that main component was metallic Ti.View full abstractDownload PDF (860K) -
Daisuke Fujita, Kazuhiro Yoshihara, Teiichi Homma1992 Volume 56 Issue 4 Pages 406-414
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMechanism of surface precipitation of boron nitride on an austenitic stainless steel which contains nitrogen and boron atoms as excess solutes is studied here. The surface covered with the boron nitride overlayer is so inert to chemisorption that it has been considered as one of the candidates for ultrahigh vacuum uses. Chemical state and crystal structure of the precipitates were investigated by using Auger electron spectroscopy (AES), Fourier transform infrared absorption spectroscopy (FT-IR), high energy electron diffraction techniques (RHEED, TED), and scanning electron spectroscopy (SEM). The observed chemical state and crystal structure showed that the precipitates were identified as hexagonal boron nitride (h-BN). Diffraction study revealed that the h-BN layers had the preferred orientation and tended to cover the surface with their basal planes (001). AES study for the surface reaction kinetics clarified the precipitation mechanism. Before the formation of h-BN started at 973 K, the surface was found to be segregated by atomic-like nitrogen atoms. At about 973 K, the nitrogen atoms began to react with boron atoms that come to the surface by bulk diffusion. During the surface reaction, the line-shape of N (KLL) Auger spectrum was found to change from the atomic state to the h-BN phase. Based on the experimental results, a model for the surface precipitation of highly oriented h-BN is proposed. The model consists of three stages: at the first stage, the excess nitrogen atoms segregate on the surface much enough to form the domains; at the second stage, the nitrogen atoms react with the boron atoms and form the h-BN grains of monolayer thickness; and at the third stage, the h-BN grains grows in a layer-by-layer way.View full abstractDownload PDF (1560K) -
Yoshinori Wakamatsu, Toshitada Shimozaki, Masami Onishi1992 Volume 56 Issue 4 Pages 415-421
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to obtain fundamental information on the development of a new Ni diffusion coating method using molten Pb as a medium for transfer of Ni atoms to an iron surface, solid state reactions of iron in molten lead containing various amounts of nickel at 1173 to 1373 K have been investigated.
A dense and uniform diffusion layer composed of γ phase was obtained on the surfaces of iron specimens annealed in Pb-Ni melts. Pb could not be detected in the diffusion layer, although Pb particles adhered to the surface of the diffusion layer. The surface concentration of Ni in the diffusion layer increases with increasing Ni content of molten Pb and the maximum value of 95 mass% was obtained at more than 4 and 5 mass%Ni at 1173 and 1273 K, respectively. The thickness of the diffusion layer increases as the Ni content of molten Pb, annealing temperature and time increase, while the surface concentration of Ni in the diffusion layer decreases with increasing annealing temperature. These results are explained from the concentration dependence of Ni activity in molten Pb and the temperature dependence of interdiffusion coefficient in the γ phase. The method used here is applicable to Ni diffusion coating on iron and steel, if sticked molten Pb can be removed from the surface of the coatings.View full abstractDownload PDF (1461K) -
Hidetoshi Terashima, Takashi Nakamura, Kusuhiro Mukai, Daisuke Izu1992 Volume 56 Issue 4 Pages 422-429
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSSlag foaming is one of the major important problems in commercial iron and steel smelting processes. It is clear from recent studies that one main cause of slag foaming is due to high speed generation of small bubbles at the slag-metal interface. Thus, analysis of bubble shape and size generated at liquid interfaces is very meaningful.
In the present study, a model for estimation of the maximum bubble size detached from a liquid interface was established from a view-point of interfacial chemistry. Bubbles electrochemically generated at a mercury-HCl/H2SO4 solution interface were directly observed through a microscope, and the effect of wettability between the two liquid phases on bubble shape and size was investigated.
The bubble size generated at the interface mainly depended on the wettability between the liquids. The bubble size increased with a decrease of wettability. The model proposed in the present study may quantitatively explain the bubble generation behavior at the interface.View full abstractDownload PDF (1439K) -
Yukio Nishikawa, Kunio Tanaka, Yoshikazu Yoshida1992 Volume 56 Issue 4 Pages 430-437
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMetal particles generated by excimer laser ablation are observed. Effects of laser conditions and target materials on particles are also studied. The ArF and KrF excimer laser beam are irradiated on Cu, Ni and Al plate targets in the vacuum. Laser plume is generated from the irradiated surface of a target. Then, thin film is deposited on a substrate. Surfaces of thin films and targets are observed by scanning electron microscope. Spectroscopic observation and mass-spectroscopic study of the plume are also carried out. The main results obtained are as follows.
(1) Thin films deposited on the substrates contain particles with diameters of 1∼10 μm. The diameter and number of particles in Al films are greater than those in Cu or Ni films. They also get smaller for lower laser fluence.
(2) Thicknesses of thin films linearly increases with laser fluences. Thicknesses obtained under KrF beams are greater than those under ArF beams.
(3) Surfaces morphologies of targets after laser irradiation differs with target materials. Corn morphology is obtained with Cu, the flat one with Ni and the lump one with Al, respectively.
(4) Laser plume contains a neutral atom and charged ions (M+ and M2+). Under ArF beams, M2+ ions are more easily generated than under KrF beams. Higher excited state is obtained in the case of higher irradiation angle. And higher intensity of optical emission is observed under higher laser fluence or higher frequency of irradiation.View full abstractDownload PDF (1628K) -
Takehiko Mae, Hiroaki Nomura, Motoshige Hibino, Satoshi Sunada, Sumiko ...1992 Volume 56 Issue 4 Pages 438-445
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of Ga content on the pitting corrosion behavior of Al and Al-Ga alloys in NaCl-H2SO4 solution was investigated by the measurements of anodic polarization curves, pitting potentials (Epit), apparent pitting corrosion rate (dI/dt), amounts of pits, surface area ratio of pitting and SEM observations of pitting surfaces for Al and Al-Ga alloys.
The main results obtained are summarized as follows:
(1) The pitting corrosion resistance of Al and Al-Ga alloys decreases with the increasing NaCl concentration and solution temperature. The pitting corrosion resistance of Al-Ga alloys decreases with increasing Ga content below 0.675 mass%. However, the pitting corrosion resistance is almost constant at high Ga content.
(2) The apparent pitting corrosion rate (dI/dt) for all the specimens used increases with increasing NaCl concentration, solution temperature and setting potentials (ΔE).
(3) The number of pits for pure Al and its surface area ratio increase with increasing NaCl concentration and solution temperature. On the contrary, the dependence of number of pits for Al-Ga alloy on the NaCl concentration and solution temperature is not so large. However, the mean size of pits is larger than that of pure Al. The increase of the mean size of pits for the alloy may be caused by the accumulation of Ga in the bottom of pits.View full abstractDownload PDF (1482K) -
Masahiro Okumiya, Yoshiki Tsunekawa, Itaru Niimi, Hiromitsu Miyahara, ...1992 Volume 56 Issue 4 Pages 446-451
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSInfluences of treating time, plasma current and plasma voltage in plasma-carburizing process on carbon content was studied using low carbon steel foils with a thickness of 0.25 mm. The increase in plasma current, plasma voltage and treating time caused the increased carbon content in specimens. Therefore, the quantitative prediction of carbon content which was varied with the treating parameters was done as follows.
The carbon content C(t) was obtained by a linear equation with the variable treating times (t) at a constant plasma current (IP),
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the slopes of lines increased proportionally to IP. At the higher IP, however, the increasing rate of C(t) decreased gradually as t increased, and the carbon content was saturated with about 1.9 mass% (t>5.4 ks, IP : 0.04 A).
The carbon content C(V) was obtained by a linear equation with the variable plasma voltages at the constant IP and t,
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where V was defined as the average voltage of those measured at every 600 seconds in discharging at the constant IP.
Consequently, the carbon content [C(V, t)] at a given V and t was calculated as follows,
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where VO was the standard plasma voltage defined as an average value of all V at each IP. Using the equations of C(V, t), the carbon content could be predicted by the treating parameters in advance of the practical plasma-carburizing process.View full abstractDownload PDF (1124K) -
Hideyuki Murakami, Kimihiro Higuchi, Toyonobu Yoshida1992 Volume 56 Issue 4 Pages 452-458
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe main purpose of this study is to develop a novel coating process by thermal plasma chemical vapor deposition (TPCVD) under reduced pressure around 3.5×104 Pa. We began with the calculation of temperature and flow fields in hybrid Ar plasmas which were operated under reduced pressure and local thermodynamical equilibrium (LTE) conditions in order to investigate its effectiveness for TPCVD. The derived results suggested that the reduced pressure operation causes two main effects; (1) heating efficiency of the exit gas is raised to about 73% because of the reduction of radiation energy loss, and (2) plasma velocity is drastically accelerated to the order of 100 m/s at the torch exit. Moreover, the excellent stability and velocity controllability of hybrid plasma were also shown. Based on these modeling works, high rate and large area coating of SiC was tried at 3.5×104 Pa by injecting SiCl4 and CH4 as reactants into Ar plasmas. During deposition, plasma tail flame revealed two distinct zones, that is, a central high intensity luminous zone and a relatively low intensity greenful one. Dense grossy SiC films with grain size of 3 to 7 nm and Vickers hardness over 3000 kgf/mm2 were deposited successfully at the maximum deposition rate of 70 nm/s on a graphite substrate in the latter zone at the deposition temperature less than 1470 K. Particularly noteworthy is that the dense film depositing area spread over 150 mm in diameter. In conclusion, these theoretical and experimental investigations have confirmed the possibility of high rate and large area ceramics deposition by TPCVD using a hybrid plasma system.View full abstractDownload PDF (1367K) -
Masahiko Sakakihara, Yukio Ichinose, Sadae Yamaguchi1992 Volume 56 Issue 4 Pages 459-463
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAmorphous BN (a-BN) films are very promising materials for the mask membrane of X-ray lithography because of their high transparency to X-rays. Characteristics of films used for the mask menbrane demand the tensile stress to Si-wafer substrate and the high optical transmittance to the He-Ne laser used for mask alignment.
It was, however, very difficult to obtain a-BN films fully satisfying such requirements as mentioned above. We tried adding carbon to a-BN films and, as the result, obtained the conditions to produce a-BNC films suitable for the mask membrane. It is naturally considered that a-BNC films as deposited change their characteristics by annealing. Then, we investigated the effects of anneal on stress in films. Vacuum-annealing over the deposition temperature resulted in the decrease of stress for a-BNC films contrary to the increase of stress in a-BN films. This fact is so well corresponding to the result that the amount of the bonded hydrogen increased in a-BNC films but decreased in a-BN films. On the other hand, for the relationship between the intrinsic stress and the total hydrogen in a-BNC films deposited at various temperatures, the stress increased with increasing total hydrogen which was opposed to the behavior of a-BN films.View full abstractDownload PDF (618K) -
Shoji Futaki, Katsuzo Shiraishi, Mikio Uemura1992 Volume 56 Issue 4 Pages 464-471
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSUltrafine particles of W, Mo, Ta and Nb have been formed by the plasma evaporation method in a “Hybrid Plasma”, characterized by the super-imposition of a DC arc jet on a radio-frequency plasma. The raw refractory metal powders were injected into the DC arc jet. All particles obtained were black in color and fluffy. Mean particle size was between 15∼50 nm. The maximum formation rate of W ultrafine particle was 41.7 g·K·s−1.
The ultrafine particle of W was heat-treated between 673∼1673 K in vacuum.
Heat-treatment above 873 K showed an increase of the mean particle size, and the oxygen content was decreased above 1073 K through the transformation of W3O to WO2 which is followed sublimation.
The ultrafine W particle and conventional W powder having a size of 1.8 μm and the mixtures of both were sintered in H2 atmosphere. In the cases of the mixture containing more than 20% of the ultrafine particle, the sintering temperature was decreased by 400 K compared to the conventional powder. Vicker’s hardness of sintered compacts was increased with the addition of the ultrafine particle.
The decrease of sintering temperature was also observed in the case of the conventional WC powder and the ultrafine particle mixture.
The mean ultrafine particle size of Mo was larger than that of W which is explained by the lower melting and boiling temperature of Mo. The heat-treatment of the Mo ultrafine particle in vacuum shows the increase in particle size over 873 K and the decrease in oxygen content over 1273 K.
The ultrafine Ta and Nb particles formed hydride TaH0.9, NbH0.89 respectively, by using H2 as a sheath gas.
The heat-treatment of Ta ultrafine particle in vacuum showed an increase in particle size above 873 K and a decrease in hydrogen content above 673 K, whereas the oxygen content was not decreased in this heat-treatment.View full abstractDownload PDF (2406K) -
Akira Kawasaki, Atsushi Hibino, Ryuzo Watanabe1992 Volume 56 Issue 4 Pages 472-480
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe burner heating test for thermomechanical evaluation of functionally gradient material in a laboratory scale has been described. A temperature difference was given by heating the ceramic side with a burner frame and cooling the metal side with water flow. The damage at the specimen surface was monitored with a microscope. A vertical crack formation at the ceramic surface was observed during cooling cycle. The test temperature for the first crack formation was defined as a thermal barrier performance value for the test sample. It has been found that the crack formation temperature is almost constant for the various samples and heating conditions, which indicates strong dependency of the thermal barrier property on the material species. The crack formation mechanism was discussed on the basis of a thermal stress analysis using a finite element method.View full abstractDownload PDF (2253K) -
Kouichi Honda, Yutaka Kagawa1992 Volume 56 Issue 4 Pages 481-486
Published: 1992
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSEffects of H2O in specimen and loading rate on the interfacial shear sliding stress in SiC fiber-reinforced LAS matrix composite have been examined using a micro-indentation technique. The results shows that the interfacial shear sliding resistance depends strongly on the existence of H2O which is contained in the composite. When the sample is completely dried, the measured shear sliding stress is constant within the measured loading rates. However, when the composite contains H2O, the interfacial shear sliding stress decreases at the loading late below 1.5 mN/s and increases at the loading late above 1.5 mN/s in comparison with the interfacial shear sliding stress of the fully-dried composites. In the dried samples, scattering of the shear sliding stress reduces in the experiment using argon atmosphere instead of air.View full abstractDownload PDF (1171K)
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