摘要
为研究金属材料在超临界流体拟临界区内的腐蚀行为,解释拟临界区内腐蚀加剧现象的形成机理,采用超临界流体反应釜腐蚀实验平台,对316L奥氏体不锈钢在375.6℃、22.5 MPa,405.6℃、22.5 MPa以及405.6℃、28.6 MPa 3种超临界水工况下进行200 h的静态腐蚀实验,并通过电子天平称量、扫描电子显微镜分析、X射线能量色散光谱仪分析和X射线衍射分析等方法对试样的腐蚀情况进行了分析。结果表明:316L不锈钢在拟临界区(375.6℃、22.5 MPa)腐蚀加剧,腐蚀速率最高,腐蚀产物最为复杂;在拟临界区的腐蚀产物为两层,外层为Fe_(3)O_(4)、Fe_(2)O_(3),内层为FeCr_(2)O_(4),而在超临界压力高参数区(405.6℃、28.6 MPa)只形成一层Fe_(3)O_(4),内层产物膜尚未形成。通过对腐蚀机理分析发现,由于超临界水在拟临界区的物性剧烈变化,动力学作用增强,加速了氧等腐蚀性介质向材料基体的迁移,加剧了腐蚀产物脱落及游离,故而产生了材料在拟临界区腐蚀加剧的现象。该研究可为超临界流体环境下改善材料抗腐蚀性能、保障我国超临界系统的安全运行提供参考。
To study the corrosion behavior of metal materials in the pseudocritical region of supercritical fluid and explain the corrosion intensification mechanism in such a region,the corrosion experimental platform of supercritical fluid reactor was used for the static corrosion test of 316L austenitic stainless steel for 200h under three supercritical conditions(375.6℃-22.5 MPa,405.6℃-22.5 MPa,and 405.6℃-28.6 MPa).The corrosion behaviors of the 316L stainless steel were analyzed by weighing with electronic balance,scanning electron microscope,energy dispersive X-Ray spectroscopy and X-Ray diffraction.The results show that 316L stainless steel has the highest corrosion rate and the most complex corrosion products in the pseudocritical region(375.6℃-22.5 MPa).The corrosion products in such a region are two layers,of which the outer layer is Fe_(3)O_(4) and Fe_(2)O_(3) and the inner layer is FeCr_(2)O_(4).However,only one layer of Fe_(3)O_(4) is formed in the supercritical high pressure parameter region(405.6℃-28.6 MPa),and the inner product film has not been formed.Through the analysis of corrosion mechanism,it is found that the physical properties of supercritical water change dramatically and the dynamic effect is enhanced in the pseudocritical region.This phenomenon accelerates the migration of corrosive media such as oxygen to the material matrix,and intensifies the abscission and dissociation of corrosion products.Therefore,the corrosion of materials in the pseudocritical region is intensified.This study provides a scientific basis for improving the corrosion resistance of materials in supercritical fluid environment and the safe operation of supercritical system in China.
作者
刘云帆
雷贤良
邓越文
苟灵通
李会雄
LIU Yunfan;LEI Xianliang;DENG Yuewen;GOU Lingtong;LI Huixiong(State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2022年第7期96-107,共12页
Journal of Xi'an Jiaotong University
基金
国家市场监督管理总局科技计划资助项目(2019MK071)
国家重点研发计划资助项目(2018YFB0604403)。
关键词
超临界水
拟临界区
腐蚀行为
腐蚀机理
supercritical water
pseudo critical zone
corrosion behavior
corrosion mechanism
