# Tag Info

## Hot answers tagged glass

41

The potassium is not added first because the potassium does not intrinsically make stronger glass, it is the substitution of a larger ion for a smaller one that does. To understand why ion exchange strengthens glass, you have to understand why the ion exchange makes the glass harder. The process of ion exchange hardening is done at a temperature that allows ...

25

Chemically-strengthened glass is similar tempered glass in that the outside of the glass is under compression, while the inside is not compressed. If all the sodium in chemically-strengthened glass were to be replaced by potassium, there would be no difference in stress between the interior and the exterior layer. How does this difference between layers ...

17

You can indeed "harden" glass by exchanging ions on the surface, but not because it turns into quartz glass. Quartz glass is mostly so robust because it has an extremely small thermal expansion coefficient, and is therefore mostly free of internal stress due to uneven cooling. Ordinary glass already gets a lot more durable when you temper it, thereby ...

7

Gold plating glass could probably be 99.99% complete. It would make a nice mirror and would probably stay unoxidized for a long time. However, if I wanted to remove the gold, I think I would rinse the glass with HF solution, or perhaps NaOH solution, either of which would find those teeny tiny gaps and undercut the whole gold plate. I don't think there ...

6

As A.K. notes, it is the substitution of larger atoms for smaller atoms that adds stress to the glass, making it stronger. So you can't increase the stress by starting with a larger metal, but you could on the other hand start with a smaller metal: Chemically strengthened lithium aluminosilicate glass (Int. Patent Application)

6

You could dealkalize the surface of a borosilicate glass to get rid of alkali ions, but I'm not aware of a method that allowed the extraction of alkali metals from the bulk of the glass. There are probably quite a few ways to modify the surface, but here's a few reported by Yashchishin and Zheplinskii [1]: Sulfur anhydride or Freon is the most widely ...

5

One candidate for reaction with the rubidium is silica, $\ce{SiO2}$. Reference [1] reports that black powders are formed when alkali metals are contacted with silica. Such powders are more stable in dry air than ordinary alkali metals. The reference suggests that electrons are imparted from the alkali metals into the silica forming an electride complex. ...

2

Not glass per se, but silica is often produced chemically by silicon alkoxide gelation to create aerogels. The problem with creating glass by some cold process would be that the reaction side-products, such as water, would have to be removed, leaving holes in a froth of glass. This is fine for creating an aerogel, but is not helpful in making solid objects, ...

2

As Long as I rinse the previous contents (milk) out, can I safely use this glass container for diluting antifreeze and putting it into my vehicle? Not sure if you are talking a bout antifreeze for the radiator system or windshield deicers, but both systems are rugged enough that the do not require very pure water to be used. A washed milk container would ...

2

"Lead crystal" usually refers to glass cut decoratively to partly resemble the facets of a cleaved crystal, so it's not really misleading, considering that most people recognise crystals by their faceted shape rather than their internal structure. I looked into "crystalline glass" after being astonished at this term in a promotion involving what looked like ...

1

Since a destructive method is allowed, the other suggestions did not work for you (despite being excellent, especially the Archimede's scales suggested by @porphyrin) and you have hot caustic soda (aka $\ce{NaOH}$), I suggest this plausible method (which, thankfully, I have never had to use). First, crush a small amount of the suspect lead glass, trying to ...

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