Corrosion properties of Ti<sub>3</sub>SiC<sub>2</sub> and Ti<sub>3</sub>AlC<sub>2</sub> in static liquid lead–bismuth eutectic at 500°C
Huiping Zhu, Xudong Liu, Baochen Chang, Xiaobo Li, Muran Qi, Yifeng Wang, Fenglei Niu, Yan Ma, Liangliang Lyu
Abstract
Abstract For lead‐cooled fast reactors and accelerator‐driven subcritical systems, the surface corrosion behavior of candidate structural materials in lead–bismuth eutectic (LBE) is a key issue, which determines whether the material is applicable. The candidate materials of two typical MAX phases, Ti 3 SiC 2 and Ti 3 AlC 2 , were immersed in static LBE with saturated oxygen concentration at 500°C for up to 3000 h. The corrosion behaviors of Ti 3 SiC 2 and Ti 3 AlC 2 were analyzed by scanning electron microscope, energy‐dispersive X‐ray, X‐ray diffraction, and Raman spectra. The experimental results showed that elements interdiffusion between LBE and sample matrix occurred on both Ti 3 SiC 2 and Ti 3 AlC 2 surfaces, which led to the formation of the diffusion layer. The dominant component of the diffusion layer is PbTiO 3 , which makes the corroded surface fragile in a stress environment. Besides, there were differences in structures of corroded sample surfaces between Ti 3 SiC 2 and Ti 3 AlC 2 . The corrosion layer of Ti 3 SiC 2 consisted of two layers, while only one single layer formed on Ti 3 AlC 2 surfaces. The stable oxide layer consisting of SiO 2 and TiO 2 can protect Ti 3 SiC 2 samples from further LBE corrosion and maintain the integrity of the surfaces. For Ti 3 AlC 2 samples, it is hard to form a continuous Al 2 O 3 protective layer, thus no stable oxide layer was detected on the corroded surfaces. Compared with Ti 3 AlC 2 , Ti 3 SiC 2 showed better corrosion resistance in LBE.