材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
51 巻 , 11 号
選択された号の論文の17件中1~17を表示しています
  • 大久保 勝夫
    2002 年 51 巻 11 号 p. 1181-1189
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 今川 博之
    2002 年 51 巻 11 号 p. 1190-1196
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 津留 豊, 玉江 裕二, 永井 陽子, 中畑 友見, 松居 克
    2002 年 51 巻 11 号 p. 1197-1202
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The galvanic cell current between a steel plate and a platinum wire cathode immersed in oxygenated lime water containing sodium chloride and various amino acids as inhibitors was measured, permitting continuous monitoring and evaluation of corrosive effects of the solution pH and of the efficacy of the corrosion inhibitors.
    A relation of log[Cl-]=0.41log[OH-]-0.17 was found in a criterion concentration between Cl- and OH- for the onset of pitting corrosion on the steel surface. It was also found that the amino acids functioned as corrosion inhibitors. Especially, the composite additive consisting of DL-glycine and DL-aspartic acid, or of DL-serin and DL-aspartic acid effectively adsorbed on the steel surface and greatly suppressed the pitting corrosion of the steel.
  • 藤井 宏明, 久保 俊裕, 清水 宏明, 片野 幸雄, 柴田 俊夫
    2002 年 51 巻 11 号 p. 1203-1209
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    It is important to evaluate the corrosion extent of buried pipes for maintaining them. But it requires much time and much cost to get corrosion data for evaluating the corrosion extent of buried pipes. So we have tried to evaluate the corrosion extent simply by using corrosion resistance based on A.C. impedance measurment method in solution containing many soluble compo-nents extracted from soil.
    We have investigated the relationship between every corrosion resistance and analysis value of water extracted from soil, weight loss by the corrosion and corrosion rate of buried ductile iron pipes and have established the simple prediction method of the depth of external corrosion by the corrosion resistance and soil quality judged visually on the spot.
  • 西川 明伸, 野中 英正
    2002 年 51 巻 11 号 p. 1210-1217
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Cathodic protection is being applied to buried heat supply pipelines in district heating and cooling systems. However, there is possibility of corrosion due to the inner jumping current occurring at insulating joints.
    In this study, a corrosion protection method which makes the bare pipe behave as if it were coated on its inner surface with resin or a resin tube was developed and evaluated. This method utilizes the behavior that the passivity of corrosion-resistant material restrains the outflow of current from its surface. As a result of various experiments, it has been found to be most effective to use a pipe made of titanium with insulating joints at both ends for reducing the inner-jumping current.
    This corrosion protection method has already been adopted at worksites and confirmed in its effect.
  • 野中 篤, 野中 英正
    2002 年 51 巻 11 号 p. 1218-1222
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to evaluate the corrosion of copper which is used as an absorber vessel material in the absorption refrigeration cycle, electrochemical measurements of copper in the condition of a thin-solution layer, which is 1mm in thickness, of concentrated aqueous solution of lithium bromide in argon atmosphere were made.
    As a result, values of corrosion rate in the condition of a thin-solution layer were 3 to 6 times larger than in the immersed condition regardless of whether there was an inhibitor or not. This difference seems to be due to the following reason. As the argon gas phase above the solution contained a little air (oxygen), the oxygen concentration was higher in the condition of a thin-solution layer than in the immersed condition. Therefore, the values of free corrosion potential in the condition of a thin-solution layer became more noble than in the immersed condition, and cathodic diffusion limit current density in the condition of a thin-solution layer increased, compared with that in the immersed condition.
  • 内田 仁, 山下 正人, 花木 聡, 香川 博行
    2002 年 51 巻 11 号 p. 1223-1228
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Titanium nitride (TiN) films were prepared onto stainless steels by nitrogen ion irradiation during titanium vapor deposition, i.e., ion mixing and vapor deposition (IVD) technique. The influence of preparation conditions on surface morphology, preferred orientation and microstructure of TiN films were investigated. The TiN films with preferred orientation of {111} or {100} plane were characterized by the respective appearance of triangular or grainy crystals, which were strongly dependent of preparation conditions. The area ratio of pinhole defects in the TiN films evaluated by electrochemical measurement successfully decreased with the orientation of plane preferring {100}. On the contrary, they increased with the orientation of plane preferring {111}. Here, the correlation between preferred orientation and pinhole defect of TiN films was discussed with the optimum preparation conditions for the corrosion-protective dry coating films.
  • 桐原 聡秀, 宮本 欽生
    2002 年 51 巻 11 号 p. 1229-1234
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 北條 恵司, 平井 清人, 安藤 柱, 秋 〓〓, 松下 真也, 佐藤 繁美
    2002 年 51 巻 11 号 p. 1235-1241
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    High temperature oxidation behavior of Si3N4-based ceramics was investigated systematically. The test has been made at 13000C in dry air environment up to 2000 hours. The Si3N4 specimens tested were as follows. a) S-1: Si3N4 added 8mass% Y2O3. b) S-2: Si3N4/SiC added 8mass% Y2O3. c) S-3: Si3N4 added 5mass% Y2O3 and 3mass% Al2O3. d) S-4: Si3N4/SiC added 5mass% Y2O3 and 3mass% Al2O3. The main conclusions are as follows. 1) Oxidized layer thickness of S-3 and S-4 were much thicker than those of S-1 and S-2. 2) Relationship between the oxidation time and oxidized layer thickness obeyed the parabolic law in all specimens. 3) The Y concentration under the oxidized layer was reduced considerably. The zone was defined as diffused layer. The thickness of diffused layer was very large in S-3 and S-4 samples. 4) Crystalline phases in the oxidized layer were mainly SiO2 and Y2Si2O7. 5) Effect of SiC composition on the oxidation behavior was slight.
  • 宮崎 則幸, 池田 徹, 小村 俊裕
    2002 年 51 巻 11 号 p. 1242-1247
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Al2O3/YAG eutectic composite has been developed for a structural material used in ultra high temperature environments more than 1500°C such as in a gas turbine. Creep behavior is one of the important material properties in ultra high temperature materials. In the present study, we propose image-based finite element analysis for estimating the steady state creep behavior of the Al2O3/YAG eutectic composite. In the image-based finite element analysis, micro-structure of the material taken by a SEM is modeled into a finite element mesh using a software for image processing. Then finite element creep analysis is carried out to obtain the steady state creep behavior of the Al2O3/YAG eutectic composite by using steady state creep constitutive equations for both Al2O3 single crystal and YAG single crystal. The results of steady state creep behavior obtained from the image-based finite element analysis are compared with the experimental results. It is found that the steady state creep behavior of the Al2O3/YAG eutectic composite is accurately estimated by the image-based finite element analysis. Furthermore, we examine the effect of volume fractions of the constituents on the steady state creep behavior of the Al2O3/YAG eutectic composite.
  • 山崎 高司, 宮本 博之, 御牧 拓郎
    2002 年 51 巻 11 号 p. 1248-1252
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Stress corrosion crack (SCC) propagation tests have been carried out in 1kmol/m3 sodium nitrite aqueous solution to investigate SCC propagation behaviour of ultra-fine grained (UFG) copper produced by equal-channel angular pressing (ECAP) technique. SCC propagation tests have been performed on Compact Tension (CT) specimens under constant load. Phenomenon of SCC propagation was estimated from the crack propagation rate (da/dt) and the stress intensity factor (KI). Relationship between the da/dt and the KI in UFG copper could be divided into region I and II. The da/dt increased with the KI in region I. The da/dt was independent of the KI and showed constant value in region II. SCC in UFG copper had propagated along grain boundary. On the other hand, the transgranular SCC propagation was observed in polycrystalline copper. The anodic dissolution mechanism should be considered for the SCC of UFG and polycrystalline coppers. The SCC propagation in UFG copper could be understood from the film rupture and dissolution if the grain boundary sliding is considered as a dominant slip event.
  • 許 金泉, 武藤 睦治
    2002 年 51 巻 11 号 p. 1253-1258
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Frictional contact interface edge appears in the fretting pair of a mechanical structure, and reduces its fatigue life. Due to the frictional force on the contact interface, the singular behavior at the edge is different from that of a bonded wedge, and is also different from that obtained by Hertz theory for elastic contact problems. In this paper, the singular stress field at a frictional contact interface edge is deduced theoretically. Based on the eigenequation which determines the singular order, the optimum geometry of the contact pad is discussed. Numerical analysis by using the boundary element method is also carried out to verify the theoretical results. It is found that the singularity depends not only on the material combination and the geometry shape of the frictional interface edge, but also on the coefficient of friction. Moreover, the singularity can be even stronger than 1/√r.
  • 松永 久生, 村上 敬宜
    2002 年 51 巻 11 号 p. 1259-1266
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 竹内 信行, 山崎 裕司, 石田 信伍
    2002 年 51 巻 11 号 p. 1267-1270
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Effects of sintering additives on mechanical and electrical properties of Gd-doped barium titanate ceramics have been studied by measuring their electrical resistivity, bending strength, and ESR spectra. The bulk density of the sample prepared by sintering at 1100°C with small amounts of BaB2O4 doped as sintering aids was as high as 90% of the theoretical value. Semiconducting BaTiO3 was obtained by sintering the BaB2O4-doped samples at 1100°C. The electrical resistivity of the 3mol% BaB2O4-doped sample sintered at 1100°C was the lowest in all samples and its PTCR jump was more than 4 orders of magnitude. In addition, the bending strength of the sample was the highest in all samples and the value was close to that of the sample sintered at 1380°C without sintering additives. The line width of the ESR signal of Gd3+ observed in the sample sintered at 1100°C with BaB2O4 was almost equal to that in the sample sintered at 1380°C without sintering additives. The result showed that in the samples doped with BaB2O4 as a sintering aids, Gd3+ ions were dissolved uniformly in BaTiO3 grains at a sintering temperature of 100°C.
  • 篠崎 征夫, 島田 一夫
    2002 年 51 巻 11 号 p. 1271-1277
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Incombustible radio wave (RW) absorbers are developed by using inorganic carbon fiber-reinforced superlightweight polymer-modified mortars in place of conventional organic materials. The RW absorbers have a satisfactory RW absorbing performance for higher frequencies abve 30MHz. The RW absorbers can also be applied to microwave absorbers which are required to be more incombustible and to be able to absorb microwaves above 1GHz. The development of such materials makes it possible to design a highly fire-resistant anechoic chamber that has not been considered impossible to make until now.
  • 大即 信明, 西田 孝弘, 皆川 浩, Wanchai YODSUDJAI
    2002 年 51 巻 11 号 p. 1278-1283
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this study is to investigate the durability of reinforced concrete member on land repaired by electrodeposition. In this study, there are two series of tests. In the first series, the reinforced concrete specimen after electrodeposition has been exposed outdoor for 2 years. Then, the durability of specimen after electrodeposition is investigated by measurement of the ratio of crack closure and the apparent coefficient of water permeability. Also, in the second series, the existing reinforced concrete member after electrodeposition has been left there for 2 years. Then, the durability of existing member after electrodeposition is investigated by measurement of ratio of crack closure, half-cell potential, polarization resistance, and carbonation depth. As a result, it can be derived that the repair effect of the electrodeposition method is maintained after the reinforced concrete repaired by electrodeposition has been exposed for 2 years.
  • 今木 敏雄, 戸倉 直
    2002 年 51 巻 11 号 p. 1284-1289
    発行日: 2002/11/15
    公開日: 2009/06/03
    ジャーナル フリー
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