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Corrosion resistance of chromized 316L stainless steel for PEMFC bipolar plates

“…Fig. 5 also shows that the abrupt concentration drop at the phase boundary between ␣-Fe (Cr-rich layer) and ␥-Fe (substrate) disappeared and changed into a diffuse boundary when the cementation was carried out for 10 h [19,21].…”

“…Considering the above-mentioned requirements, the pack cementation technique appears to be an attractive surface treatment to improve corrosion resistance without increasing electrical resistance. The pack cementation technique has been employed extensively to improve corrosion resistance or increasing the surface hardness and the experimental methods and the diffusion mechanism during cementation process is well established [18][19][20][21][22][23].…”

Formation of Al and Cr Dual Coatings by Pack Cementation on SNCM439 Steel

“…Since the partial pressures of Alhalides are normally much higher than those of Cr-halides, the coatings of Cr-Al alloys are only possible when the activity of Al in the pack is 2-3 orders below that of Cr. [18][19][20] There are two possible ways to overcome this problem: (1) using a "lean" pack where the metal powders contain higher Cr and lower Al concentrations; 21,22) or (2) performing dual instead of single heating processes first by treating at 925°C and then at 1 150°C. 20) Meanwhile, chromium carbide (Cr23C6) was reported to form at surface due to the rapid outward diffusion of carbon during simultaneously chromizing and aluminizing.…”

A novel powder aluminizing technology assisted by direct current field at low temperatures

“…By heating the parts to be coated in a closed container to a high temperature for a period, a diffusion coating of desired composition and thickness could be produced on the parts. Conventional pack aluminizing cementation was usually carried out above 1173 K for several hours, since the rate of the process was very slow at lower temperature because it was latticediffusion dominant [5][6][7][8][9][10].…”