304SS在800-900℃在饱和水蒸气下中氧化动力学研究3×10atm

摘要由于不锈钢有良好的耐腐蚀性，不锈钢在高温条件下的氧化问题就成为阻碍其使用寿命的重要因素。本文介绍了一些不锈钢在高温下的氧化行为和氧化动力学理论。研究了 304 不锈钢在高温水蒸气下的氧化行为，对该不锈钢材料的氧化动力学进行了一些研究。并且利用 SEM、EDS 和 XRD 对氧化层的形貌和成分进行了观察分析，得到了如下结论：

（1）在高温条件下，不锈钢水蒸气氧化的主要特征是在水蒸气中的氧化速率比在空气中要快得多。水蒸气对不锈钢的氧化破坏比较严重。

（2）304 不锈钢在水蒸气下的氧化动力学基本服从抛物线规律，氧化速度随温度升高而加快。80939

（3）氧化层的形貌特征为内外双层结构，内外氧化层的厚度在高温水蒸气氧化过程中不断增加。外层的主要成分是 Fe 元素的氧化物，疏松多孔，但是均匀且连续，表面基本上与试样原表面平行。内层为尖晶石型的铁铬氧化物，而且内层致密，起伏较大，不连续。随着氧化时间的延长，靠近晶界处内层与基体界面上会形成深色的富 Cr 层，该层能有效降低氧气向基体内部的扩散速度。不锈钢被水蒸气氧化后，氧化膜因其压应力、热应力及生长应力，氧化层应变所积蓄的能量易导致氧化膜剥落，直接造成钢的壁厚减少。

毕业论文关键词：不锈钢，高温氧化，水蒸气，氧化动力学

Abstract Because of the good corrosion resistance of stainless steel, the oxidation of stainless steel at high temperature is an important factor to hinder its service life。In this paper, the oxidation behavior and oxidation kinetics of some stainless steel at high temperature are introduced。The oxidation behavior and the oxidation kinetics of 304 stainless steel in high temperature water vapor was studied in this paper。And I used SEM, EDS and XRD to observe and analyze the morphology and composition of the oxide layer。The conclusion can be obtained as follows:

(1)In the high temperature condition, the main characteristic of steam oxidation of stainless steel is that the oxidation rate in water vapor is much faster than that in air。Water vapor oxidation of stainless steel is more serious。

(2)The oxidation kinetics of 304 stainless steel under water vapor obeys the parabolic law,and the oxidation rate increases with the increase of temperature。

(3)The morphology of the oxide layer is characterized by internal and external double layer structure, and the thickness of the inner and outer oxide layer increases continuously during the high temperature steam oxidation process。The main component of the outer layer is the oxide of the Fe element,porous, but uniform and continuous,and the surface is essentially parallel to the original surface of the sample。The inner layer is spinel type iron chromium oxide,and the inner layer is dense, undulating and discontinuous。With the extension of oxidation time, the dark rich Cr layer can be formed on the interface between the inner layer and the substrate near the grain boundary layer。The layer can effectively reduce the diffusion rate of oxygen into the substrate。 Afterstainless steel water vapor oxidation,oxide film due to its compressive stress, thermal stress and growth stress, the oxide layer of strain energy easily lead to peeling off the oxide film,resulting in a reduction of the wall thickness of steel。

Keywords: Stainless steel, high temperature oxidation, water vapor, oxidation kinetics

第一章绪论 1

1。1 不锈钢 1

1。1。1 奥氏体不锈钢 1

1。2 304SS在800-900℃在饱和水蒸气下中氧化动力学研究3×10atm:http://www.youerw.com/cailiao/lunwen_94266.html