Avtor/Urednik		Kocijan, Aleksandra; Milošev, Ingrid
Naslov		Elektrokemijske in XPS-raziskave kobaltovih zlitin v simulirani fiziološki raztopini
Prevedeni naslov		Electrochemical and XPS studies of cobalt-based alloys in a simulated physiological solution
Tip		članek
Vir		Mater Tehnol
Vol. in št.		Letnik 38, št. 5
Leto izdaje		2004
Obseg		str. 339-43
Jezik		slo
Abstrakt		The electrochemical behaviour and the composition of the passive layer of Co-Cr-Mo and Co-Ni-Cr-Mo alloys in simulated physiological solution, with and without the addition of the complexing agents EDTA and citrate, were studied by electrochemical techniques and X-ray photoelectron spectroscopy. The electrochemical results show that both Co-based alloys passivate very well in a simulated physiological solution. Their electrochemical characteristics are similar to those of chromium metal. The sputter-depth profiles prove the formation of a chromium-enriched/cobalt-depleted passive layer on the Co-Cr-Mo alloy and a chromium-enriched/nickel- and cobalt-depleted passive layer on the Co-Ni-Cr-Mo alloy. Chromium oxide is the major constituent of the passive layer on the Co-Cr-Mo and Co-Ni-Cr-Mo alloys, despite the fact that it is only the second and third metal component, respectively, of the bulk alloys. Molybdenum oxide is, in both cases, present as a minor constituent of the passive layer. The Ni-free alloy is not significantly affected by the addition of the complexing agents, whereas the Co-Ni-Cr-Mo alloy is affected by both. The complexing agents affect the passivation of both alloys. Cobalt, molybdenum and nickel are depleted throughout the passive layer due to the preferential dissolution at the oxide/electrolyte interface and the complexing of metal cations by EDTA.
Izvleček		Elektrokemijske lastnosti zlitin Co-Cr-Mo in Co-Ni-Cr-Mo ter kemijsko sestavo pasivne plasti na površini obeh zlitin v simulirani fiziološki raztopini (SFR) ter vpliv kompleksantov EDTA in citrata smo raziskovali z uporabo elektrokemijskih tehnik in XPS-analizo. Rezultati elektrokemijskih meritev so pokazali, da se zlitini Co-Cr-Mo in Co-Ni-Cr-Mo dobro pasivirata v SFR in da se vedeta podobno kot krom. Globinski profili potrjujejo tvorbo pasivne plasti na površini zlitine Co-Cr-Mo, obogatene s kromom in osiromašene s kobaltom, na površini zlitine Co-Ni-Cr-Mo pa so obogatene s kromom in osiromašene z nikljem ter kobaltom. Kromov (III) oksid je glavni gradnik pasivne plasti na površini obeh zlitin, ne glede na to, a(i je po kemijski sestavi šele drugi in tretji kovinski konstituent v zlitinah. Molibdenov oksid je v obeh primerih zastopan kot manjšinski gradnik pasivne plasti. Dodatek kompleksantov ne vpliva bistveno na elektrokemijske lastnosti zlitine Co-Cr-Mo, bolj pa na zlitino Co-Ni-Cr-Mo. Pri obeh zlitinah pa lahko opazimo spremembe v sestavi pasivne plasti. Vsebnost kobalta, niklja in molibdena je osiromašena na celotnem področju oksidne plasti zaradi preferenčnega raztapljanja na meji oksid/elektrolit na račun kompleksiranja kovinskih ionov z EDTA.
Deskriptorji		COBALT CHROMIUM ALLOYS NICKEL MOLYBDENUM MATERIALS TESTING CORROSION ELECTROCHEMISTRY SPECTROMETRY, X-RAY EMISSION