Structure and composition of trivalent chromium process (TCP) films on Al alloy
Xuecheng Dong1, Peng Wang, Sandip Argekar
1Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0012, USA.
Abstract:
Neutron reflectivity (NR) and X-ray reflectivity (XRR) were used to determine the structure and composition of trivalent chromium process (TCP) films on aluminum alloy AA-2024. Two deposition methods were developed: immersion and electroassisted (EA) deposition. The EA deposition method was designed to guarantee a well-defined film with a uniform structure and minimum contamination from Al and additives in the precursor solution. Quantitative NR and XRR analysis of the EA-TCP film confirmed linear growth as a function of deposition time. By analyzing both NR and XRR data on as-prepared and dried films, the film composition was determined to be Cr(2)O(3) x iH(2)O x x(ZrO(2) x jH(2)O) (i = 2.10 +/- 0.55, j = 1.60 +/- 0.45, and x = 0.85 +/- 0.14).
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