Effect of Oxidizing Agents on Corrosion Resistance of Commercially Pure Titanium in Nitric Acid Solution

Effect of metal ions in a heated nitric acid solution on the corrosion behavior of a titanium–5% tantalum alloy in the hot nitric acid condensate

“…Satoh et al also observed the same tendency for the corrosion of Ti in boiling nitric acid, and explained this behavior to be a result of the dissolution and accumulation of Ti ions (Ti 4+ ) in the boiling nitric acid, which act as corrosion inhibitors and make the TiO 2 layer having high corrosion resistance [10]. On the other hand, in our study of the corrosion of Ti-5Ta in the condensate, the corrosion rate of the Ti-5Ta increased linearly with the nitric acid concentration in the condensate, as shown in Fig.…”

“…This assumption is y = 2.688×10 2 x 6.752×10 3 R 2 = 9. Satoh et al reported that the thickness of the oxide film on the surface of Ti increased drastically, and the oxide film composition changed from lower oxides, such as TiO and Ti 2 O 3 , to the higher oxide TiO 2 with increasing nitric acid concentration in the boiling nitric acid [10]. By contrast, our experimental results, which were obtained in the condensate, showed that the thickness of the oxide film was nearly constant, and the oxide film was composed of mainly lower Ti oxides, regardless of the nitric acid concentration.…”

“…Some alternative materials for nitric acid applications, such as Ti base alloys [6,7] and Zr base alloys [8], were developed and have been investigated for utilization in actual plant components. It is well known that Ti and its alloys have superior corrosion resistance in nitric acid solutions due to the passive TiO 2 film that is present on the surface, even at high nitric acid concentrations [9], particularly in the presence of oxidizing ions such as Cr 2 O 2À 7 and Ce 4+ [10,11]. These Ti alloys remain in the passive region at high oxidizing potentials, and thus the enhanced dissolution observed for stainless steels does not occur.…”

Titanium and Titanium Alloys

“…When the solution is not refreshed, buildup of Ti 4 þ ions leads to a more protective, dehydrated titanium oxide [43]. Other metal ions, such as Fe 3 þ , Ru 3 þ , Rh 3 þ , Ce 4 þ , and Cr 6 þ , and oxidizing ions, such as VO 2 þ and Cr 2 O 7 2 À , also inhibit high-temperature corrosion [44]. Only tantalum alloying additions significantly improved the corrosion resistance and yielded titanium alloys that were virtually insensitive to changes in temperature and acid concentration [45].…”

Werkstoffe für die Salpetersäure‐Industrie

“…8 1.4306 in boiling nitric acids, according to R. F. Maness [8] Saure [7]. Desestret [9] Tabelle 2 zeigt analoge Ergebnisse, zeigt aber auch eine gewisse Schwache des Titans in reinen, siedenden Salpetersauren [12] (Abb. 9 ist der EinfluS von Fe"' -und CrV'-Gehalten bei 2-bis 13-molarer Saure ersichtlich [8].…”