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Control of non-equilibrium microstructure and function of oxide scales formed in high temperature oxidation of metalic materials for high efficiency energy comversion

控制金属材料高温氧化过程中形成的氧化皮的非平衡微观结构和功能，实现高效能量转换

基本信息

批准号：
16360361
负责人：
MARUYAMA Toshio
金额：
$ 9.02万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

(1)Quantitative prediction of void formation in a growing scales in high temperature oxidationEquations have been proposed for evaluation of chemical potential distribution, ionic fluxes and its divergence in a growing oxide scales. The divergence was proved to be the good measure for evaluating the void formation. The validity was experimentally confirmed in magnetite scales formed in high temperature oxidation of iron.(2)High temperature oxidation of ferritiv Fe-Cr alloys for interconnects in solid oxide fuel cell (SOFC) and electrical conductivity of the oxide scale.Simulating the operation condition of SOFC, high temperature oxidation of Fe-16Cr alloys was conducted in the dual atmosphere, in which specimens were exposed air for the cathode and the mixture of H2O (97%) and H2 (3%) at 1073 K. The continuous protective Cr2O3 scales were formed on both sides. The growth rates were quite similar, indicating the major defect was interstitial ion of Cr in two cases.The estimation of the … More oxygen potential distribution clarified that the oxygen potential is low almost the whole region in scales. This fact predicted the reason why the electrical conductivity of the Cr2O3 scales were high. Applied external currents retarded the growth rate of Cr203 on the cathode and enhanced it on the anode. The equations were proposed for evaluating the scale growth rate under the external current and the equations predicted the growth rate in the long term exposures.(3)Control of microstructure development and design of the function of the scales.The summary of this project is the following(1)The quantitative prediction of microstructure development is possible with diffusion coefficients of constituent ions as a function of oxygen potential.(2)For controlling microstructure, it is dispensable to design the diffusivity. The appropriate doping is an possibility for the design of the microstructure.(3)The evaluation of chemical potential distribution and divergences of ionic fluxes is very powerful for controlling microstructures and designing the function of scales. Less

(1)高温氧化过程中孔隙形成的定量预测提出了评价氧化过程中化学势分布、离子通量及其发散的方程。散度是评价孔隙形成的良好指标。在铁的高温氧化形成的磁铁矿中，实验证实了该方法的有效性。(2)固体氧化物燃料电池（SOFC）互连用铁素态Fe-Cr合金的高温氧化及氧化层的电导率。模拟SOFC的工作条件，在1073 K的双气氛下对Fe-16Cr合金进行了高温氧化，试样以空气为阴极，H2O（97%）和H2（3%）的混合物为阴极。两侧形成连续的Cr2O3保护层。两个病例的生长速率非常相似，说明主要缺陷是Cr的间质性。对该区氧势分布的估计表明，在尺度上，该区氧势几乎全是低的。这一事实预测了Cr2O3鳞片电导率高的原因。外加电流抑制了Cr203在阴极上的生长速度，增强了其在阳极上的生长速度。建立了外源电流作用下的尺度生长率评价方程，并对长期暴露下的尺度生长率进行了预测。(3)微结构开发控制和尺度功能设计。本课题总结如下：(1)利用组成离子的扩散系数作为氧势的函数，可以定量预测微观结构的发展。(2)为了控制微观结构，对扩散系数进行设计是必不可少的。适当的掺杂是设计微结构的一种可能。(3)评价离子通量的化学势分布和发散对控制微观结构和设计尺度功能具有重要意义。少