Electrochemical study of Aluminum-Fly Ash composites obtained by powder metallurgy

Marin, E; Lekka, M; Andreatta, F; Fedrizzi, L; Itskos, G; Moutsatsou, A; Koukouzas, N; Kouloumbi, N

dc.contributor.author	Marin, E	en
dc.contributor.author	Lekka, M	en
dc.contributor.author	Andreatta, F	en
dc.contributor.author	Fedrizzi, L	en
dc.contributor.author	Itskos, G	en
dc.contributor.author	Moutsatsou, A	en
dc.contributor.author	Koukouzas, N	en
dc.contributor.author	Kouloumbi, N	en
dc.date.accessioned	2014-03-01T02:08:43Z
dc.date.available	2014-03-01T02:08:43Z
dc.date.issued	2012	en
dc.identifier.issn	10445803	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29728
dc.subject	Al	en
dc.subject	Composites	en
dc.subject	Corrosion mechanisms	en
dc.subject	Fly ash	en
dc.subject.other	Aggressive media	en
dc.subject.other	Aluminum metal matrix composites	en
dc.subject.other	Brake rotors	en
dc.subject.other	Chemical compositions	en
dc.subject.other	Class C fly ashes	en
dc.subject.other	Composite samples	en
dc.subject.other	Corrosion mechanisms	en
dc.subject.other	Corrosive medium	en
dc.subject.other	Crevice corrosion	en
dc.subject.other	Electricity load	en
dc.subject.other	Electrochemical behaviors	en
dc.subject.other	Electrochemical studies	en
dc.subject.other	Energy dispersive x-ray spectroscopy	en
dc.subject.other	Engine blocks	en
dc.subject.other	Fe-Rich intermetallics	en
dc.subject.other	Galvanic coupling	en
dc.subject.other	Green products	en
dc.subject.other	Lignite-fired power stations	en
dc.subject.other	Mean particle diameter	en
dc.subject.other	Open circuit potential measurements	en
dc.subject.other	Partial detachment	en
dc.subject.other	Powder metallurgy technologies	en
dc.subject.other	Pure aluminum	en
dc.subject.other	Scanning Kelvin probe force microscopy	en
dc.subject.other	SEM observation	en
dc.subject.other	Volta potential	en
dc.subject.other	Aluminum powder metallurgy	en
dc.subject.other	Composite materials	en
dc.subject.other	Corrosion resistance	en
dc.subject.other	Degradation	en
dc.subject.other	Dissolution	en
dc.subject.other	Electrostatic precipitators	en
dc.subject.other	Fly ash	en
dc.subject.other	Hardness	en
dc.subject.other	Industrial applications	en
dc.subject.other	Intermetallics	en
dc.subject.other	Metallic matrix composites	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Sintering	en
dc.subject.other	Wear resistance	en
dc.subject.other	X ray spectroscopy	en
dc.subject.other	Aluminum	en
dc.title	Electrochemical study of Aluminum-Fly Ash composites obtained by powder metallurgy	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.matchar.2012.04.004	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.matchar.2012.04.004	en
heal.publicationDate	2012	en
heal.abstract	In this paper, two different ASTM C 618 Class C fly ashes (FA) were used for the production of aluminum metal matrix composites (MMCs) using powder metallurgy (PM) technology. Calcareous FAs were sampled from the electrostatic precipitators of two different lignite-fired power stations: from Megalopolis, Southern Greece (MFA) and from Kardia, Northen Greece (KFA), under maximum electricity load. FAs were milled in order to reduce the mean particle diameter and Aluminum-FA composites containing 10% and 20% of FA were then prepared and compacted. The green products were sintered for 2 h at 600°C. Sintered Al-FA MMCs showed increased hardness and wear resistance suggesting their possible use in industrial applications for example in covers, casings, brake rotors or engine blocks. As most possible industrial applications of MMCs not only require wear resistance, but also corrosion resistance in different mild aggressive medias, this paper aims to study the electrochemical behavior of FA MMCs in order to evaluate their corrosion resistance. The morphology and chemical composition of the phases in the Aluminum-FA composite samples were investigated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Moreover, topographic and Volta potential maps were acquired by Scanning Kelvin Probe Force Microscopy (SKP-FM). Volta potential maps provide information about the electrochemical behavior of the different phases in absence of electrolyte. The electrochemical behavior was investigated by Open Circuit Potential measurements and potentiodynamic polarization, while the corrosion mechanisms were studied by SEM observations after different times of immersion in a mild corrosive medium. In all cases it could be stated that the addition of the FA particles into the Al matrix might cause an increase of the hardness and mechanical properties of the pure aluminum but deteriorates the corrosion resistance. The degradation phenomena occurring on the FA containing samples might be related to the following mechanisms: 1) Partial detachment or dissolution of the FA soluble phases, in particular based on Si, Fe and Ca; 2) dissolution of the Al matrix surrounding the FA particles due to crevice corrosion; 3) Al localized dissolution due to galvanic coupling between the Fe-rich intermetallics and the matrix. © 2012 Elsevier Inc. All rights reserved.	en
heal.journalName	Materials Characterization	en
dc.identifier.doi	10.1016/j.matchar.2012.04.004	en
dc.identifier.volume	69	en
dc.identifier.spage	16	en
dc.identifier.epage	30	en