Dealloying Kinetics of Cu1 − x Ti x on SiO2 Using In Situ X‐Ray Diffraction

Abstract

We study the dealloying of Ti from Cut_xTi x (x ~ I0 atom percent) alloy films on oxidized Si substrates in the 6 5 temperature range of 375 to 490~ and an estimated u2 partial pressure of -i0-to i0-Tort. Reaction products were determined to be TiO and Ti203 and possibly TiO2 at the free surface, and TiO at the SiO2 interface, according to Rutherford backseattering spectrometry and Auger electron spectroscopy. We found that the Cu lattice parameter varies linearly with Ti concentration, and this variation is independent of temperature in this composition range. As a consequence, we were able to study the dealloying kinetics using in situ x-ray diffraction by monitoring the time dependence of the Cu lattice parameter. We observe that the reaction kinetics obey a parabolic rate law, i.e., X~,re~ct~d = kt, with a single activation energy of 1.6 _+ 0.i eV, suggesting that one process governs dealloying kinetics over this temperature range. In addition, we note a pronounced composition dependence, in that the reaction rate increases sharply with increasing Ti concentration. These observations suggest that Ti diffusion in Cu is the rate-limiting kinetic process for the dealloying reactions in this temperature regime. We model the dealloying reaction and in so doing estimate the diffusion coefficient for Ti in these alloy films.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-08 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 138.251.14.35 Downloaded on 2015-03-08 to IP

Influence of composition on corrosion behavior of as-cast Cu–Zr alloys in HCl solution

“…Dealloying is a corrosion process whereby one or several electronegative constituents of an alloy are preferentially removed from the alloy due to their high reactivity, leading to an altered residual structure [1][2][3][4][5][6][7][8]. Today, it is widely recognized that dealloying phenomena play an important role in many alloys, for example, in the corrosion of brass [9], stainless steel [10,11], the aluminum alloy 2024 [12], and the high-Pd dental alloys [13].…”