Akademik Veri Yönetim Sistemi
I-manager's Journal on Future Engineering and Technology JFET, cilt.2, sa.1, ss.24-29, 2006 (Hakemli Dergi)
In this study, alloying and coating effects of active metals (Ti, Zr and Hf) alloyed with Sn were investigated on reactive wetting of Al2O3 at 1273K. To investigate the effect of alloying, Sn-6wt.%Ti, Sn-6wt.%Zr and Sn-6wt.% Hf alloys were prepared for sessile drop tests on polished Al2O3. Average contact angles measured were 68o, 60o and 68.5o, respectively. For the effect of coating, Al2O3 substrates were coated with TiO2, ZrO2 and HfO2, and sessile drop tests were done with pure Sn. Average contact angles measured were 36o, 28 o and 34.7o, respectively. In both cases, polished and coated (with TiO2, ZrO2 or HfO2) Al2O3 substrates, the measured contact angles were equal to or lower than 70o. Substrates were effectively wetted by Sn alloyed with active metals (Ti, Zr, Hf) as well as pure molten Sn. XRD, DTA, metallography techniques and SEM were used to characterize the braze alloys and cross sections of the wetted substrates. XRD results for wetted substrate cross-sections revealed the intermetallics TiAl3, ZrAl, and HfAl as reaction products. The most important result stemming from this work is that a reaction between active metal components and the substrate does not necessarily lead to lower contact angles.