TY - JOUR
T1 - Synthesis and characterization of chromate conversion coatings on GALVALUME and galvanized steel substrates
AU - Domílnguez-Crespo, M. A.
AU - Onofre-Bustamante, E.
AU - Torres-Huerta, A. M.
AU - Rodríguez-Gómez, F. J.
AU - Rodil, S. E.
AU - Flores-Vela, A.
N1 - Funding Information:
The authors acknowledge the financial support given by UNAM through the DGAPA PAPIIT IN 115603-project, IPN through SIP-20090561 and 20090499 projects, and SNI-CONACYT through the 61354 project. The authors thank Mr. Ivan Puente L. for the SEM analyses and L. Baños for XRD measurements.
PY - 2009
Y1 - 2009
N2 - The morphology, composition, and corrosion performance of chromate conversion coatings (CCCs) formed on GALVALUME (Fe-Al-Zn) and galvanized steel (Fe-Zn) samples have been studied, and different immersion times (0, 10, 30, and 60 seconds) have been compared. The coated surfaces were analyzed using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements in a NaCl solution (3 wt pct). The electrochemical measurements were carried out using the polarization resistance, Tafel, and ac impedance methods. A nonuniform growth of the CCCs having a porous morphology and cracks that appear extended to the base metal was observed. The XRD patterns show that the coatings mainly consist of CrO3, Cr2 O3, and traces of Cr2O7-2. The electrochemical results show that GALVALUME presents a better behavior than that of the galvanized steel alloys at each dipping time. The SEM micrographs show that the galvanized steel treatments resulted in the formation of a more uniform film, but their protection barrier broke down faster than that of the GALVALUME samples in contact with the aggressive media. The samples that underwent the lowest degree of dissolution were those with a dipping time of 30 seconds. The difference in the corrosion protection given by the two substrate types could be attributed to the structural properties, grain size, composition, and roughness, which affect oxygen diffusion.
AB - The morphology, composition, and corrosion performance of chromate conversion coatings (CCCs) formed on GALVALUME (Fe-Al-Zn) and galvanized steel (Fe-Zn) samples have been studied, and different immersion times (0, 10, 30, and 60 seconds) have been compared. The coated surfaces were analyzed using light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical measurements in a NaCl solution (3 wt pct). The electrochemical measurements were carried out using the polarization resistance, Tafel, and ac impedance methods. A nonuniform growth of the CCCs having a porous morphology and cracks that appear extended to the base metal was observed. The XRD patterns show that the coatings mainly consist of CrO3, Cr2 O3, and traces of Cr2O7-2. The electrochemical results show that GALVALUME presents a better behavior than that of the galvanized steel alloys at each dipping time. The SEM micrographs show that the galvanized steel treatments resulted in the formation of a more uniform film, but their protection barrier broke down faster than that of the GALVALUME samples in contact with the aggressive media. The samples that underwent the lowest degree of dissolution were those with a dipping time of 30 seconds. The difference in the corrosion protection given by the two substrate types could be attributed to the structural properties, grain size, composition, and roughness, which affect oxygen diffusion.
UR - http://www.scopus.com/inward/record.url?scp=67650498952&partnerID=8YFLogxK
U2 - 10.1007/s11661-009-9856-7
DO - 10.1007/s11661-009-9856-7
M3 - Artículo
SN - 1073-5623
VL - 40
SP - 1631
EP - 1644
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 7
ER -