The corrosion resistance of the steel grades 1.4512 and 1.4509 and 1.4301, which are commonly used for the hot-end of automotive exhaust systems, against NaCl- and CaCl2-induced high temperature corrosion has been investigated. For that purpose cyclic exposure tests in atmospheres with different partial pressures of O2 and H2O have been performed at 650 and 750 °C. An experimental plan has been established, by means of which the influences of a salt layer and a salt contaminated glass fibre insulation mat have been investigated. Corroded specimen have been examined by means of optical- and scanning electron microscopy and energy dispersive X-ray spectroscopy. To get a better understanding of the thermochemical reaction behaviour of the tested materials, chemical analysis of corrosion products has been done. Based on the experimental results and thermodynamic calculations a reaction mechanism is proposed. To investigate the correlation between the laboratory tests and the field behaviour of real exhaust components, a post mortem study of used parts has been conducted. The corrosion attack of field parts was examined by means of 3-D microscopy and the corrosion products have been analysed via X-ray fluorescence spectroscopy. The influence of high temperature corrosion on the corrosion resistance of tested steel sheets against a wet, chloride containing electrolyte has been studied electrochemically. Thereto, current-density-potential curves of specimen, which already experienced NaCl- and CaCl2-induced high temperature corrosion, have been established.
|Translated title of the contribution
|NaCl- and CaCl2-induced high temperature corrosion of automotive exhaust components
|Published - 2018
Bibliographical noteembargoed until 20-07-2023
- high temperature corrosion
- wet corrosion
- automotive exhaust