Fluoroboric Acid and Zinc

August 23, 2012 6:52 AM

Will hydrogen tetrafluoborate (fluoroboric acid) dissolve zinc?

My boss wants me to use fluoroboric acid but I am reluctant to do so for many reasons. If I can prove to him that the acid will damage zinc, tin, or lead, then I can kill the whole idea. I read the wikipedia entry on fluoroboric acid, but I don't know enough chemistry to figure this out.

posted by yesster to Science & Nature (5 answers total)

The microfabrication and metal etchant literature I've collected suggests that zinc is very easily attacked (by everything from dilute HCl to dilute HNO₃ to, notably, HF) and in fact looks like the least resistant elemental metal on a list of two dozen. Although fluoroboric acid is not mentioned, a look online shows a correlation across materials between etch susceptibilities to HF and HBF₄ (presumably due to the voraciousness of fluorides). I would present this correlation, along with zinc's known susceptibility to HF, as evidence to your boss.
posted by Mapes at 7:19 AM on August 23, 2012 [1 favorite]

Best answer: The MSDS says it will corrode steel, zinc, aluminum and copper. Check page 4.
posted by jeffch at 7:20 AM on August 23, 2012 [1 favorite]

The BF4- ion is mostly stable and inert, but in solution hydrolyses back into F- and BF3 in low amounts. F- is quite capable for damaging zinc, as Mapes notes.
posted by bonehead at 7:25 AM on August 23, 2012 [1 favorite]

Best answer: If you need papers as more ammunition, here's one link that shows the hydrolysis of BF4- in aqueous and mixed aqueous solutions pretty clearly---look at the pH values in Table 1.
posted by bonehead at 8:05 AM on August 23, 2012 [1 favorite]

Response by poster: Great answers, thank you. Marked as best the ones with references.
posted by yesster at 11:06 AM on August 23, 2012