TY - JOUR
T1 - Characterization and corrosion behaviour of CoNi alloys obtained by mechanical alloying
AU - Olvera, S.
AU - Sánchez-Marcos, J.
AU - Palomares, F. J.
AU - Salas, E.
AU - Arce, E. M.
AU - Herrasti, P.
N1 - Funding Information:
The authors are grateful to the Spanish Ministry of Science and Innovation ( MAT2012-37109-C02-02 , MAT2010-18432 and SIP-IPN (20130361) ) for their financial support. S. Olvera also thanks CONACYT and SIP-IPN for their grants. Special thanks are given to Dr. M. A. Laguna-Marco and Prof. C. Prieto for their comments, discussion and invaluable support during the XAS analysis. We would like to thank the Spline CRG beamline staff at ESRF for assistance during the XAS experiments.
PY - 2014/7
Y1 - 2014/7
N2 - CoNi alloys including Co30Ni70, Co 50Ni50 and Co70Ni30 were prepared via mechanical alloying using Co and Ni powders. The crystallinity and short-range order were studied using X-ray diffraction and X-ray absorption spectroscopy. The results show that the milling process increases the number of vacancies, especially around the Co atoms, while the milling time decreases the crystalline size and enhances the crystallinity. X-ray photoelectron spectroscopy was used to characterise the chemical composition of the samples surface. The magnetic properties were analysed using zero-field cooling, field cooling and a magnetic hysteresis loops. The magnetic saturation moment is approximately 1.05 μB/atom; this value decreases with the mechanical alloying time, and it is proportional to the cobalt concentration. The polarization and impedance curves in different media (NaCl, H 2SO4 and NaOH) showed similar corrosion resistance values. The corrosion resistance increased in the order NaCl, H2SO 4 and NaOH. A good passivation layer was formed in NaOH due to the cobalt and nickel oxides on the particle surfaces.
AB - CoNi alloys including Co30Ni70, Co 50Ni50 and Co70Ni30 were prepared via mechanical alloying using Co and Ni powders. The crystallinity and short-range order were studied using X-ray diffraction and X-ray absorption spectroscopy. The results show that the milling process increases the number of vacancies, especially around the Co atoms, while the milling time decreases the crystalline size and enhances the crystallinity. X-ray photoelectron spectroscopy was used to characterise the chemical composition of the samples surface. The magnetic properties were analysed using zero-field cooling, field cooling and a magnetic hysteresis loops. The magnetic saturation moment is approximately 1.05 μB/atom; this value decreases with the mechanical alloying time, and it is proportional to the cobalt concentration. The polarization and impedance curves in different media (NaCl, H 2SO4 and NaOH) showed similar corrosion resistance values. The corrosion resistance increased in the order NaCl, H2SO 4 and NaOH. A good passivation layer was formed in NaOH due to the cobalt and nickel oxides on the particle surfaces.
KW - Extended X-ray absorption fine structure spectroscopy
KW - Mechanical alloying
KW - Nickel/cobalt alloy
KW - X-ray absorption near-edge spectroscopy
KW - X-ray diffraction
KW - X-ray photoelectron spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=84899027162&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2014.03.022
DO - 10.1016/j.matchar.2014.03.022
M3 - Artículo
SN - 1044-5803
VL - 93
SP - 79
EP - 86
JO - Materials Characterization
JF - Materials Characterization
ER -