TY - JOUR
T1 - Incorporation of iridium into electrodeposited rhenium-nickel alloys
AU - Cohen Sagiv, Maayan
AU - Eliaz, Noam
AU - Gileadi, Eliezer
N1 - Funding Information: This research was conducted with financial support from the US Air Force Office of Scientific Research (AFOSR, grant number FA9550-10-1-0520 ) as well as from the Israel Department of Defense (grant number 4440258441 ). The authors thank Dr. L. Burstein, Dr. Yu. Rosenberg and Dr. Z. Barkay from the Wolfson Applied Materials Research Center at Tel-Aviv University for their help in XPS, XRD and ESEM work, respectively. We also thank M. Levenshtein for his help in preparation of metallurgical cross-sections.
PY - 2013/1/15
Y1 - 2013/1/15
N2 - Rhenium (Re), a refractory metal that has gained significant recognition as a high performance engineering material, is mostly used in military, aircraft and aerospace applications, as well as for catalysis in the petrochemical industry. However, its performance at high temperature in humid air is limited by the formation of rhenium heptoxide (Re2O7), which penetrates the grain boundaries and causes brittleness. Improvement of this is being sought through the incorporation of iridium (Ir) into Re deposits. To this end, suitable plating baths for Re-Ir-Ni coatings were developed. These alloys were deposited from different aqueous solutions on copper substrates under galvanostatic conditions, in a three-electrode cell. The plating bath consisted of iridium tri-chloride, ammonium perrhenate and nickel sulfamate as the electroactive species, and citric acid as the complexing agent. The effects of bath composition and operating conditions on the Faradaic efficiency (FE), partial current densities, as well as on the thickness of the coatings and their composition were studied. Re-Ir-Ni coatings as thick as 18 μm, with Re-content as high as 73 at.% and Ir-content as high as 29 at.%, were obtained, using different plating baths. A mechanism of the electrochemical process was suggested. It was found that both an HCP Ir0.4Re0.6 phase and an HCP Ni phase with nanometric crystallites were formed, possibly together with a hexagonal nickel hydride (Ni2H) phase.
AB - Rhenium (Re), a refractory metal that has gained significant recognition as a high performance engineering material, is mostly used in military, aircraft and aerospace applications, as well as for catalysis in the petrochemical industry. However, its performance at high temperature in humid air is limited by the formation of rhenium heptoxide (Re2O7), which penetrates the grain boundaries and causes brittleness. Improvement of this is being sought through the incorporation of iridium (Ir) into Re deposits. To this end, suitable plating baths for Re-Ir-Ni coatings were developed. These alloys were deposited from different aqueous solutions on copper substrates under galvanostatic conditions, in a three-electrode cell. The plating bath consisted of iridium tri-chloride, ammonium perrhenate and nickel sulfamate as the electroactive species, and citric acid as the complexing agent. The effects of bath composition and operating conditions on the Faradaic efficiency (FE), partial current densities, as well as on the thickness of the coatings and their composition were studied. Re-Ir-Ni coatings as thick as 18 μm, with Re-content as high as 73 at.% and Ir-content as high as 29 at.%, were obtained, using different plating baths. A mechanism of the electrochemical process was suggested. It was found that both an HCP Ir0.4Re0.6 phase and an HCP Ni phase with nanometric crystallites were formed, possibly together with a hexagonal nickel hydride (Ni2H) phase.
KW - Electrodeposition
KW - Induced codeposition
KW - Rhenium-iridium-nickel alloys
UR - http://www.scopus.com/inward/record.url?scp=84870231824&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.electacta.2012.10.094
DO - https://doi.org/10.1016/j.electacta.2012.10.094
M3 - مقالة
SN - 0013-4686
VL - 88
SP - 240
EP - 250
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -