Effect of cyclic oxidation on electrochemical corrosion of type 409 stainless steel in the simulated muffler condensates

Cyclic oxidation resistance of ferritic stainless steels used in mufflers of automobiles

“…Titanium and niobium were identified on the surface of AISI 441 steel oxidized after immersion in condensate solution. But sulfur was not identified on the samples oxidized after immersion in condensate solutions as reported in literature [6]. Sato and…”

“…The chemical composition of AISI 439 and AISI 441 steels is shown in Table 1 and without immersion in condensed solution (TOP) [6]. Table 2 shows the experimental procedure.…”

“…For Li et al [6], the chloride and sulfate ions, and the low pH are most responsible for the corrosion of the muffler, considering that the sulfur content in the fuel, pollution of the atmosphere, and the rate of motion of the vehicle are also important factors which contribute to the corrosion of the muffler.…”

“…The concentration of the metallic vacancies depends on the rate of creation and elimination of vacancies. If the rate of vacancy creation is higher than the rate of vacancy elimination, the oxide film loses cohesion and suffers localized disruptions [6], as occurred on the surface of the TOC AISI…”

“…The cyclic oxidation behavior of AISI 409 steel is found in literature [6,7,9]. In this work, the oxidation behavior of AISI 439 and AISI 441 ferritic steels previously immersed in condensate was evaluated and compared with the cyclic oxidation behavior of the same steel without immersion in condensate, at 300°C, under an atmosphere of synthetic air in a tubular oven.…”