Electrical characterization of waterside corrosion films formed on ZrNb(1%)O(0.13%)

Oxide films formed by water oxidation at 360°C on ZrNb(1%)O(0.13%) for several durations (50-300 days) were studied by impedance spectroscopy (IS) in gaseous atmosphere. The electrical behavior of oxide layers was investigated as a function of the temperature (25-300°C) at constant oxygen partial pressure (0.3 Pa). Cole-Cole diagrams suggest a frequency-temperature equivalence. A simple electrical model has been derived from the as-deduced 14 decade master curve. Equivalent circuit includes a series association of two layers exhibiting different dielectric properties: a dense layer near the oxide-metal interface and a porous layer at the waterside. Electronic conductivity is predominant within the whole temperature range, but ionic contribution was proposed to increase for temperature higher than 170°C. During the parabolic oxidation step, the oxide thickness of the barrier layer increases but oxide growth would not be only a geometrical one. The kinetic modification to a constant oxidation rate was observed to be correlated to the increase of the dense layer thickness. Such a behavior suggests that the mechanism controlling oxidation rate is not a pure mechanism of oxygen diffusion through this layer. Finally, a qualitative model of activated electrons transport based on an hopping mechanism was proposed in order to take into account that the Arrhenius diagrams of both total conductivity and dispersion factor are characterized by a break point with two activation energy values.     

Mössbauer Study of the Influence of Fe-Si-N Liquid in the Synthesis of β-Si3N4 from Silica

Mössbauer spectra of the products obtained by carbothermal reduction and distribution of silica in the presence of iron in the temperatures range 1200^o to 1540^o were studied. The preponderance of β- Si₃N₄ over the α form at a higher reaction temperature were assumed to be related to the formation of an Fe-Si-N liquid. The liquid did not alter its composition with the variation of reduction-temprature, Iron had no effect on the reaction mechanism below 1300^oC.     

熔融 NaCl-(Na,K)_2SO_4引起的 Fe-Cr 合金的热腐蚀

本文采用电化学方法研究了 Fe-Cr 合金在800℃、熔融 NaCl-(Na,K)_2SO_4中的腐蚀行为,并对腐蚀产物进行了观察和分析。结果表明,提高合金 Cr 含量可以改善合金耐蚀性能。氧化-硫化是Fe5Cr、Fe10Cr 合金腐蚀破坏的主要方式;氧化膜的熔融反应是 Fe20Cr、Fe25Cr 合金加速腐蚀的主要原因。同时,氧化膜的机械破裂也加速了合金的腐蚀。     

Color characteristics of Cu-Zn-Al alloys

ＣＯＬＯＲＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＣｕ－Ｚｎ－ＡｌＡＬＬＯＹＳ￣①Ｌｉ，Ｂａｏｍｉａｎ；Ｚｈａｎｇ，Ｘｉｕｈｕａ（ＳｈｅｎｙａｎｇＩｎｓｔｉｔｕｔｅｏｆＧｏｌｄＴｅｃｈｎｏｌｏｇｙ，Ｓｈｅｎｙａｎｇ１１００１５）ＣＯＬＯＲＣＨＡＲＡＣＴＥＲ...     

机械合金化CuRECr合金的显微组织结构及性能分析

利用机械合金化和真空烧结技术制备CuRECr25和CuRECr50合金，讨论了机械合金化不同球磨时间、球料比等工艺参数对合金显微组织结构、物理机械性能，含氧量、含氮量等的影响，并且与CuCr25、CuCr50合金进行了物理机械性能比较。研究结果表明：CuRECr合金组织均匀、细微，具有强度、硬度高等特点，为改进CuCr系电真空接触材料开辟了新途径。     

高铝钛镍基合金晶粒度的研究

研究了对高温镀镍基高温金晶粒度的影响因素。以便减少晶粒度不合格废品，结果表明，在冶炼工艺和变形量一定的条件下，碳含量、高温带加热时间和终轧温度是影响晶粒度的关键因素。     

Cu-Cr合金高温氧化行为分析

该文用热分析天平，结合金相、X射线衍射(XRD)、扫描电镜(SEM)和能谱(EXD)研究了Cu—Cr合金在不同温度下的氧化行为。结果表明，Cu—Cr合金在700℃-900℃氧化符合抛物线规律，其最外层氧化膜为CuO，内层为Cu2O和Cr2O3，铬有助于提高合金的抗氧化能力。     

漫谈钛合金在舰船上的应用

钛合金优良的耐海水腐蚀性能、高的比强度、无磁性等特点,使其在船用领域大有潜力可为,我国的船用钛合金经过近40年的研究开发,基本能满足舰艇不同强度级别的需求,在舰船上应用具有明显的社会效益和经济效益,值得进一步应用推广。本文介绍了国内外舰船用钛合金的开发及应用情况。对钛合金在鱼雷发射水缸、高压气瓶、一回路危急冷却器、声扫雷具、二回路泵、阀及管系、声纳导流罩、螺旋桨等方面的应用作了重点介绍。