CP-Ti在含氟离子硝酸中表面附着物形成研究

钛具有优良的耐蚀性能,可长期工作在高浓度的沸腾硝酸介质中,是商业后处理较为理想的设备用材。本文采用SEM,EDS,XRD,XPS等表征手段对CP-Ti在含氟离子硝酸中试样表面出现的白色附着物进行分析,并解释其形成机理。结果表明：氟离子浓度在50 ppm以下时,CP-Ti腐蚀速率呈现由大到小并趋于稳定的规律；氟离子浓度在50 ppm及以上时,腐蚀速率呈现由大到小再变大的“v”型规律。试样表面的白色附着物的物相为TiO₂,其形成机理为：先是试样表面多孔膜的形成；其次是TiO₂以多孔膜上的孔为基点进行生长、脱落。

Formation mechanism of surface attachment of CP-Ti in nitric acid containing fluoride ions

_{:Titanium has excellent corrosion resistance and can be used for long-term operation in boiling high concentration nitric acid medium. It isan ideal material for reprocessing equipment. In this paper, SEM, EDS, XRD and XPS characterization methods were used toanalyzethe white attachment of the surface of CP-Tiin nitric acid with fluorine ion and explain its formation mechanism. The results show that when the concentration of fluorine ions is below 50 ppm, the corrosion rate of CP-Ti appears from large to small and tends to be stable. When the concentration of fluorine ions is 50 ppm and above, the corrosion rate appears from large to small and tends to large presents the "V" pattern. The phase of the white attachment of the surface of CP-Ti is TiO2. The formation mechanism of the attachment is divided into two steps:firstly, the formation of porous film on the surface of the CP-Ti; secondly, The TiO2 is grown on the pore of porous film as the base point and thenshedding.}