Aluminum alloys are the most important part of all shaped castings manufactured, especially in the aerospace and automotive industries. This work focuses on the corrosion properties of the heat-hardening aluminum alloys commonly used for production of automotive castings AlSi7Mg0.3 and on self-hardening AlZn10Si8Mg. Iron is a common impurity in aluminum cast alloy and its content increases by using secondary aluminum alloys. Therefore, experimental materials were developed, with chemical composition according to standards (primary alloys) and in states with an increasing content of Fe. The experimental aluminum alloys are briefly discussed in terms of their chemical composition, microstructure, mechanical properties and corrosion behavior. Corrosion properties were examined using three types of corrosion tests: exposure test, potentiodynamic tests, and Audi tests. Corrosion characteristics of materials were evaluated using stereo, optical and scanning electron microscopy, energy dispersive X-ray analysis, too. Correlation of pit initiation sites with microstructural features revealed the critical role of iron-rich phases, silicon particles and corresponding alloy matrix.

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Stainless steels usually suffer localized corrosion, such as pitting and crevice corrosion, in chloride containing oxidizing environments. Their corrosion resistance depends on materials chemical composition, microstructure, heat treatment, surface finishing, and also on environment character (composition of electrolyte, temperature, pH, flow, etc.). The subject of the work is investigation of mechanical (grinding) and combined (grinding + pickling) surface treatment effect on corrosion behavior of stainless steel AISI 316Ti. The selected properties of surfaces are determined including surface roughness, surface-free energy, topography (by atomic force microscopy) and chemical composition using scanning electron microscopy. Corrosion susceptibility of the specimens with ground or ground and pickled surfaces to local corrosion has been studied by the three types of corrosion tests (exposure test, potentiodynamic polarization, and electrochemical impedance spectroscopy). The experiments enable not only to compare corrosion resistance after different surface treatment, but to follow response of the surface state on corrosion mechanism of the different experimental methods

The current paper investigates effects of various surface treatment techniques such as grinding, garnet blasting, and shot peening on the corrosion rate and behavior of austenite stainless steel of type AISI 316 Ti. The exposure to different corrosive solutions usually accompanying the coastal and industrial environments (sodium chloride and ferric chloride), as well as a combination of the two was considered. The corrosion behavior of AISI 316 Ti under these test conditions was investigated using immersion tests and electrochemical impedance spectroscopy together with optical scanning electron microscopy, in order to observe and to assess the changes in the surface configuration and topography such the shapes, distribution, and dimensions of the resulting pits. The presented results clearly show the relatively higher corrosive effect of ferric chloride, and the increased corrosion rate under greater surface roughness values, which imply greater real surface area and capillarity effects.