论文部分内容阅读
为了提高生物质电厂锅炉过热器的耐熔盐腐蚀性能,采用电化学方法研究了T91耐热钢在不同温度KCl·Na Cl熔盐中的腐蚀行为。采用扫描电镜及X射线衍射仪分析腐蚀形貌及腐蚀产物物相组成,研究了温度对T91耐热钢熔盐热腐蚀性能的影响。结果表明:腐蚀初期,T91耐热钢腐蚀较快,其腐蚀电化学阻抗谱呈典型的受氧化剂粒子扩散控制的特征;随着腐蚀的进行,T91耐热钢表面逐渐形成了Fe Cr2O4晶尖石型氧化膜,腐蚀速率显著降低;腐蚀后期电化学反应速度主要受金属腐蚀荷电粒子在氧化膜中的迁移速率控制;随着腐蚀温度的升高,T91耐热钢的自腐蚀电流密度逐渐增加,其耐腐蚀性能减弱;根据Arrhenius公式计算得出T91在KCl·Na Cl熔盐体中的腐蚀反应活化能为33.235 k J/mol。
In order to improve the molten salt corrosion resistance of boiler superheater in biomass power plant, the corrosion behavior of T91 heat-resisting steel in molten salt of KCl · NaCl at different temperatures was studied electrochemically. The corrosion morphology and phase composition of corrosion products were analyzed by scanning electron microscopy and X-ray diffraction. The influence of temperature on hot corrosion of molten salt of T91 heat-resistant steel was studied. The results show that the corrosion of T91 heat-resisting steel is rapid at the initial stage of corrosion, and the electrochemical corrosion resistance spectrum is typical controlled by the diffusion of oxidant particles. With the progress of corrosion, the surface of T91 heat-resisting steel gradually forms Fe Cr2O4 crystal spinel Type oxide film, the corrosion rate decreased significantly. The electrochemical reaction rate at the late stage of corrosion was mainly controlled by the migration rate of metal-charged particles in the oxide film. With the increase of the corrosion temperature, the self-corrosion current density of the T91 heat- The corrosion resistance of T91 in KCl · NaCl molten salt was calculated to be 33.235 kJ / mol based on Arrhenius formula.