Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Metalurji ve Malzeme Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2010
Öğrenci: ŞAFAK HALICI
Danışman: MEHMET KADRİ AYDINOL
Özet:In this study, Mg, Sn, Cd, Bi and Sb containing, five binary, three ternary and two quaternary different alloys to be used in a Valve-Regulated Lead-Acid (VRLA) batteries have been studied in terms of their mechanical and electrochemical properties. The investigated properties are hardness, passivity, corrosion rate, hydrogen gassing and the conductivity of the passive film. All electrochemical tests were carried out in 3.75 M H2SO4 solution by using open-circuit potential, anodic polarization, polarization resistance measurement and gas collection techniques. The results showed that while the minimum hardness values were observed in Pb and Pb-Bi alloy, Mg containing alloys have the highest hardness values among all alloys. According to corrosion measurements, lowest icritical value was obtained for Pb, Pb-Bi and Pb-Sn, which reached to passivation region earlier than others. Passive film formation was seen for all specimens. The noble Ecorr value and minimum corrosion rates belonged to Pb and Pb-Mg. Pb-Bi and Pb-Cd have the highest gas evolution rate. Besides, there were not seen much difference in the gassing behavior of Pb-Sn and Pb-Sb alloys. Mg is found to have a superior effect on hydrogen gassing. Addition of Sn, as an alloying element, to lead increases the conductivity of the passivation layer. Mg containing alloys did not show good conductivity characteristic. As a result, Mg containing alloy seemed to have an important role because of the desired hardness, corrosion and, gas evolution behavior. However, conductivity of passivation layer of these alloys came up to be low due to the higher tendency of Mg to oxidation. Even so, Mg seems to be a promising alloying element for lead grid alloys in Valve-Regulated Lead-Acid (VRLA) batteries.