Steam oxidation behavior of Y-bearing cladding tube with aluminizing coating

Abstract

A kind of Y-bearing ferritic/martensitic fuel cladding tube with qualified dimensions, acceptable mechanical properties as well as good flattening and flaring performance was manufactured recently by our group. In this paper, to improve and further evaluate its oxidation resistance, the cladding tube was aluminized firstly and then subjected to high temperature steam oxidation at 1200°C for 8 h. The results indicated that aluminizing coating with gradient content of Al was prepared on the tube successfully. And the matrix microstructure was transformed from tempered martensite into ferrite during aluminizing. Weight gains after high temperature steam oxidation were 72.7 and 1.48 mg cm −2 for the bare and aluminized tubes, respectively. The latter one exhibited better oxidation resistance due to the generated dense aluminum oxide film. Meanwhile, Kirkendall pores were formed near oxidation surface and should be eliminated for the real application of the aluminized tube in the future.

The effect of aluminide coating on the steam oxidation behavior of SS321 steel at 700 °C

“…According to the mentioned cases, the presence of steam or water vapor in the atmosphere can accelerate the release of Al to the outside and protect the substrate from oxidation by forming Al 2 O 3 . This has been confirmed in several studies [22,23]. This mechanism can be explained by considering the presence of H The cross-sectional image of Al 321 after 100 h of steam oxidation at 700 °C is shown in figure 4(c).…”

Synthesis of novel colorless polyimides from benzimidazole diamines with various linearity

“…The CTE values of PBIIs range between 43 and 52 ppm K −1 . It is reported that the in‐plane orientation depending on the interchain interaction and linearity is associated to the CTE values 66–68 . 5b‐HPMDA displays a lower CTE value than 5a‐HPMDA, which is accordant to the aforesaid opinion, because 5b with the strong linearity induces PBII backbones to the compact packing and powerful interaction between chains, inhibiting the motions of molecular chain segments.…”