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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Corrosion and Wear Studies of Cr3C2NiCr-HVOF Coatings Sprayed on AA7050 T7 Under Cooling

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Author(s):
Magnani, M. [1] ; Suegama, P. H. [1] ; Espallargas, N. [2] ; Fugivara, C. S. [1] ; Dosta, S. [2] ; Guilemany, J. M. [2] ; Benedetti, A. V. [1]
Total Authors: 7
Affiliation:
[1] Univ Estadual Paulista, Inst Quim, Dept Fisicoquim, BR-14801970 Araraquara, SP - Brazil
[2] Univ Barcelona, CPT Thermal Spray Ctr, Dept Ciencia Mat & Engn Met, E-08028 Barcelona - Spain
Total Affiliations: 2
Document type: Journal article
Source: JOURNAL OF THERMAL SPRAY TECHNOLOGY; v. 18, n. 3, p. 353-363, SEP 2009.
Web of Science Citations: 19
Abstract

In this work, cermet coatings were prepared by high-velocity oxygen-fuel (HVOF) technique using a Diamalloy 3007 powder. The influence of the spray parameters on corrosion, friction, and abrasive wear resistance was studied. The samples were obtained using the standard conditions (253 L/min of oxygen and 375 L/min of compressed air), higher oxygen flux (341 L/min), and higher carrier gas flux (500 L/min). The coatings were characterized using scanning electron microscopy (SEM), and x-ray diffraction (XRD). X-ray diffraction and SEM studies showed well-bounded coating/substrate interface, pores, metallic matrix, chromium oxides, carbides, and carbides dissolution into the matrix. In comparison with the standard condition, the sample prepared using higher oxygen flux showed the highest carbide dissolution because of the high temperature achieved in the spray process. When the carrier gas flux was increased, the sample showed denser structure because of the higher particle velocity. The friction and abrasive wear resistance of the coatings were studied using rubber wheel and ball-on-disk tests. All samples showed similar sliding and abrasive behavior, and all of them showed better performance than the aluminum alloy. The electrochemical behavior was evaluated using open-circuit potential (E (OC)) measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization curves. The coating prepared with higher carrier gas flux showed the highest corrosion resistance in 3.5% NaCl solution and probably no pitting attack to the substrate occurred even after around 26 h of test. Tests performed for longer immersion times showed that the total impedance values significantly decreased (6 and 4 times) for samples sprayed using standard and higher oxygen flux, and no great change for sample sprayed using higher carrier gas flux was observed. The last sample presents a corrosion resistance around 200 times higher than the others. (AU)