为初步研究钴粒电镀镍层在无中子辐照的压水堆稳态工作条件下服役的可行性及极端事故工况对电镀镍层的影响,先后 将镀镍钴粒在2 MPa氦气环境下400°C、600°C热处理240 h、0.5 h。 用扫描电镜对电镀镍层的表面和断面形貌进行了表征,用能谱仪分析了镀层与基体的界面元素扩 散情况。结果表明镍镀层在居里温度358 °C附近的热膨胀系数突变以及钴基体在427 °C附近的 相变不会对镍镀层造成破坏性损伤,界面的元素互扩散使镀层与基体的结合更加紧密。

In order to preliminarily investigate the feasibility of nickel electroplated Co-pellets working in non-neutron irradiated steady state pressurized water reactor and influence of extreme accident on electroplated nickel coating, the nickel plated Co-pellets are heat treated at 400 °C, 600 °C in 2 MPa helium environment for 240 h, 0.5 h, respectively. The surface and fracture morphology of the electroplating nickel layer are characterized by scanning electron microscope. The diffusion of interface elements between coating and substrate is analyzed with energy dispersive spectrometer. Results show that the abrupt change of thermal expansion coefficient near Curie temperature 358 °C of nickel layer and the phase transition of cobalt near 427 °C will not cause destructive damage to nickel coating. The element inter-diffusion of interface makes the combining of coating and substrate more closely.