"The dissolution mechanism of titanium in hydrofluoric acid was studied by collecting the hydrogen evolved during the dissolution reaction. A concentration range of 0.05 N to 0.50 N and a temperature range of 15°C to 45°C were employed for the determination. Values of the reaction order and energy of activation were determined for both pure titanium and the alpha solid solutions of oxygen in titanium and found to be the same within experimental limits. This indicated that the reaction giving rise to hydrogen evolution on the surfaces of both pure titanium and the TiOx alloys was the same. The order of the reaction was approximately (3/4) and the activation energy was 6.9± 0.7 kcal/mole. These measurements were shown to be indicative of a diffusionally controlled process. The reaction involved the penetration and attack or removal of a sub-oxide layer with subsequent mass transfer of HFun to the surface and direct chemical attack. Difference effect measurements made on some TiOx alloys indicated that an electrochemical reaction was also occurring on the surface. The large value of the difference effect constant, 9.5, indicated that a secondary process was affecting the surface of the TiOx alloys so as to render them more than 100% polarizable as predicted by an equation published in previous literature.
The reaction mechanism proposed from this study was the penetration and/or removal of a sub-oxide film on the surface of the titanium with subsequent direct chemical attack. Diffusionally controlled chemical and electrochemical dissolution processes were thought to be occurring simultaneously on the surface"--Introduction, pages ii-iii.
Straumanis, Martin E., 1898-1973
James, William Joseph
Lorey, G. Edwin
Schlechten, A. W.
Materials Science and Engineering
M.S. in Metallurgical Engineering
U. S. Atomic Energy Commission
Missouri School of Mines and Metallurgy
xi, 139 pages
© 1960 John Leigh Ratliff, All rights reserved.
Thesis - Open Access
Titanium -- Metallurgy
Corrosion and anti-corrosives
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Link to Catalog Record
Ratliff, John L., "A dissolution rate study in hydrofluoric acid of titanium and the alpha solid solutions of oxygen in titanium" (1960). Masters Theses. 4177.