Development of the protecting method for hydrogen(and its isotopes) permeation through metallic pipes by cathodic polarization

金属管道氢（及其同位素）渗透阴极极化防护方法的研制

基本信息

批准号：
16360373
负责人：
FUKATSU Norihiko
金额：
$ 9.47万
依托单位：
Nagoya 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

The permeation of hydrogen through the pipe made of Fe-Cr-Al heat-resisting alloy (Cr22%, Al5%, Fe63% usually called "Kanthal Alloy") was measured by coulometric titration method. Even without any pretreatments, the measured permeability coefficient was found about one thousandth of that of usual heat-resisting Fe-Cr alloy. The measured value was nearly equal with that of alumina ceramics of the compatible thickness with the oxide layer formed on the metallic pipe, which suggests that the hydrogen permeation through the Fe-Cr-Al alloy pipe is controlled by the alumina layer formed on the surface of the pipe.The electromotive force established across the oxide film formed on the surface of the Fe-Cr-Al pipe and its polarization effect were studied in order to examine the possibility of cathodic protection of the hydrogen permeation. By emf measurement the hydrogen potential in the alloy substrate was confirmed to be maintained at high value due to the chemical polarization effect which … More had been already pointed out by us. The effect of cathodic polarization on the hydrogen permeation, however, was not confirmed clearly because the oxide film was made unstable by polarization in the reducing condition and also the permeation rate was naturally at very low value. Therefore, the pipe of polycrystalline alumina ceramics with porous platinum electrodes on inner and outer sides were employed in the place of the oxide film formed on the surface of the metallic pipe and the effect of polarization on this sample was studied in detail.It was confirmed that hydrogen was incorporated or released from the bulk of alumina on the change of the polarization conditions. This phenomenon was analyzed by calculating the hydrogen chemical potential profile in the polarized specimen. Based on this analysis, the solubility of hydrogen into the commercial polycrystalline alumina was determined. After a period of cathodic polarization by imposing 0.8V at 1573 K, it was observed that the permeation through the alumina pipe was perfectly blocked. Therefore, the possibility of cathodic protection of hydrogen permeation of a metallic pipe was confirmed if the stable alumina film doped with bivalent elements was formed on the surface of the pipe.The new phenomena such as the extraordinary incorporation of hydrogen at initial stage of oxidation of the metal, the super saturation of hydrogen into alumina, and the new mechanism relating with the hydrogen/proton electrode reaction were observed in the course of this study. The possible explanations of these phenomena were also given in the sub works of this research. Less

通过COULOMENTRICTICRICTITRATIC滴定法测量了通过由Fe-Cr-Cr-Cr-Al耐热合金制成的氢（CR22％，Al5％，Fe63％）的渗透。即使没有任何预处理，也发现了测得的渗透系数约为通常的耐热Fe-Cr合金。测得的值几乎与兼容厚度的氧化铝陶瓷与在金属管上形成的氧化物层相等，这表明通过Fe-Cr-Cr-al-Al铝管控制的氢渗透由在管道表面上形成的氧化铝层控制。氢渗透的阴极保护。通过EMF测量，由于化学极化效应，合金底物中的氢潜力被确认保持高值，而化学极化效应已被我们指出。然而，由于在还原条件下极化使氧化物膜变得不稳定，而且渗透率自然在非常低的值时，氧化物膜因极化而使氧化物膜变得不稳定，因此阴极极化对氢渗透的影响没有清楚地得到证实。因此，在金属管表面形成的氧化物膜上使用了多孔铂电极的多晶氧化铝陶瓷的管道，并详细研究了极化对该样品的效果。IT证实，IT已确认氢被氢化或释放在极化条件上的大量铝中。通过计算极化标本中的氢化学势曲线来分析这种现象。基于此分析，确定了氢对商业多晶氧化铝的溶解度。经过一段时间的阴极极化，通过在1573 K处施加0.8V，观察到通过氧化铝管的渗透被完全阻塞。因此，如果在管道表面上形成了掺杂二价元素的稳定氧化铝膜对金属管的氢渗透的可能性。学习。这些现象的可能解释也在这项研究的子工作中给出了。较少的