Upsilon - 30-9-2015 at 18:50
I happened to stumble upon this abstract:
http://www.sciencedirect.com/science/article/pii/00223093709...
I was aware that extremely hot molten phosphoric acid attacks glass, but the article also mentions that this process creates a protective layer of
silicon phosphate, which reduces the mechanical strength of the glass, but apparently offers protection against glass-etching fluoride ions. Can
anyone confirm this? It seems very interesting.
BromicAcid - 30-9-2015 at 19:05
Just let me take a second to connect the two topics...
http://www.sciencemadness.org/talk/viewthread.php?tid=62676
Upsilon - 30-9-2015 at 19:10
Huh, I could have sworn I didn't find any other topics. Oops.
j_sum1 - 30-9-2015 at 19:12
I have heard this before on these boards.
If I recall, the consensus was that the weakening was significant, the protective layer was of indeterminant value and that with fluorine you just
don't take any chances.
Do a search and see what you find. A mod might even merge threads for you.
[edit]
Beaten by two posts.
That was fast.
[Edited on 1-10-2015 by j_sum1]
Upsilon - 30-9-2015 at 19:16
Well, while on the topic, does this mean that phosphoric acid is a feasible candidate for dissolving very unreactive metal oxides, such as TiO2? Since
it is clearly capable of dissolving SiO2.