Pickling and passivation
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Our factory has two pieces of equipment that have just been installed (including the pipelines); each piece has a volume of around 5 m³ and is made of titanium. I would like to carry out acid washing and passivation on them. I plan to purchase 2 m³ of nitric acid to prepare a 20% concentration nitric acid solution in a total volume of 10 m³. This solution will be pumped into the equipment, where it will stay for two hours before being drained. Is this approach feasible? Should 5% hydrofluoric acid be added? It seems to only serve a purpose in pickling, without providing any passivation effect. Using boron clay is also quite troublesome; please advise.
Does titanium need to be pickled with acid? Just cleaning it is enough.
It seems that titanium doesn’t require pickling; pickling of stainless steel is more common, while I’ve never heard of such a practice for titanium
Titanium materials need to be pickled and passivated.
The pickling and passivation of titanium materials is intended to remove the original oxide layer containing impurities and to form a new, dense oxide layer. In fact, the main consideration is how to remove the oxide layer on the titanium surface through pickling; once pickling is complete, as long as there is oxygen present, titanium will quickly form a new oxide layer.
Is my plan feasible? I think it’s a bit expensive
Is titanium washed with nitric acid? I really haven’t used this before
Titanium can be pickled with acids, but not for passivation; it is generally used only to remove surface oxidation and the like. I also manufacture titanium tubes, which are subjected to vacuum heat treatment at the time of delivery, without any pickling process~~~ Last edited by ivan_wong on 2009-4-21 16:12 ]
The purpose of pickling titanium is not to remove the surface oxide layer, but rather to eliminate other impurities on the surface. There are two methods for this treatment: 1) sandblasting; 2) pickling: cleaning with a mixture of nitric acid and hydrofluoric acid can prevent hydrogen absorption by titanium.
Pickling the titanium surface is primarily aimed at removing gas contaminants and iron contamination resulting from the manufacturing process, as well as to prepare it for welding. Titanium dissolves very easily in hydrofluoric acid (HF); it begins to dissolve when the concentration of HF is less than 1%. Therefore, for the pickling of titanium, hydrofluoric acid is commonly used as the main component of the pickling solution. When hydrofluoric acid is used as the pickling solution, it should be mixed with nitric acid to prevent hydrogen absorption by titanium during the pickling process.
Yes, it is also possible to hire a professional cleaning company to carry out the task