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Fireside corrosion of T24 steel and HVOF NiCr-coated counterparts is investigated. The samples were exposed to different deposits of NaCl, KCl, Na2SO4 and K2SO4 at 650 ºC for 360 h in dry air. The deposit with the highest chloride content (NaCl-KCl) was the most aggressive followed by the ones combining chlorides and sulfates. In contrast, the sulfate-based salts did not produce severe damage. The NiCr coating maintained the integrity of the substrate but the chlorides induced a great attack on the coating. The formation of K2CrO4 and the penetration of chlorides are identified as the main factors of this attack.

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The corrosion mechanisms of T24, T92, VM12, and AISI 304 steels are studied under the influence of NaCl–KCl, NaCl–Na2SO4, and KCl–K2SO4 salt mixtures in a dry air atmosphere at 650°C for 15 days. NaCl–KCl was the most aggressive deposit and AISI 304 stainless steel exhibited the highest corrosion resistance. There was no relation between the Cr content of the ferritic steels and their corrosion resistance in NaCl–KCl. In contrast, the resistance of high‐Cr steels was better when exposed to NaCl–Na2SO4 and KCl–K2SO4. The high‐Cr and the low‐Cr steels were more susceptible to NaCl–Na2SO4 and to KCl–K2SO4, respectively.

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Corrosion susceptibility of the A6005 alloy reinforced with n‐TiB2 was studied through electrochemical tests. The mechanical alloying (MA) technique was used as the processing route and a posterior hot extrusion was employed to consolidate the powders. Bulk samples were characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and microhardness tests. The combination of both MA processing and 5 wt% n‐TiB2 addition in the aluminum matrix produced 61% increase of microhardness. Electrochemical tests were performed in 3.5 wt% NaCl solution to assess the effect of MA processing and TiB2 presence on corrosion behavior. The corrosion resistance of the samples processed by MA increased slightly compared with the base A6005 alloy. The amorphous Al2O3 phase formed during MA processing was the cause of this increase, providing continuity to the passive layer. Furthermore, the addition of TiB2 on the sample processed by MA did not significantly affect corrosion resistance. Polarization tests confirmed that the reinforced sample had similar icorr to that of the unreinforced alloy, and cyclic polarization tests revealed that pit nucleation sites were localized in the interface between Al2O3 and the aluminum matrix.