What is the etch rate for a pH 14 solution on silica glass at room temperature?

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    Etching Glass
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Discussion Overview

The discussion revolves around the etch rate of silica glass when exposed to a solution with a pH of 14 at room temperature. Participants explore the potential rates of etching, considering various factors that may influence the outcome.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Claude inquires about the order of magnitude for the etch rate of silica glass in a pH 14 solution, suggesting possible rates in nm/hr, microns/hr, or mm/hr.
  • One participant notes that the etch rate will depend on the specific components of the solution, suggesting that strong bases like AlOH may lead to a very low rate, possibly nm/month.
  • Another participant proposes that if the etch rate were to be categorized among the initial options, it would likely be in the microns/hr range, citing visible etching at that concentration, though noting that the rate is not sufficient to dissolve the glass beakers completely.

Areas of Agreement / Disagreement

Participants express differing views on the etch rate, with no consensus reached on a specific value or range. The discussion reflects multiple competing perspectives on the etching process.

Contextual Notes

The discussion does not clarify the specific composition of the pH 14 solution, which may significantly impact the etch rate. Additionally, the assumptions regarding the visibility of etching and the conditions under which it occurs are not fully explored.

Who May Find This Useful

Researchers or practitioners interested in materials science, particularly those studying the chemical interactions of strong bases with silica glass.

Claude Bile
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Greetings,

Just a quick question.

I would like to know what order of magnitude the etch rate will be for a solution with a pH of 14 on silica glass (flat surface at room temp) - are we talking nm/hr? microns/hr? mm/hr?

Thanks,

Claude.
 
Last edited:
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It's going to depend on what is in the solution.

Lots of strong bases (AlOH is one) are stored in silica glass. So at room temp, I'll ballpark that the rate is going to be very low.Perhaps nm/month?

You could etch glass with HF...
 
If those were my three choices, I would say it is microns/hr. Visible etching is observed during that time at that concentration so the scale must be larger than a wavelength of light (500 to 900 nm) but the rate is insufficient to completely dissolve the bottom out of glass beakers (thickness of 1-2 mm) containing pH 14 liquid.
 
Thanks for the responses.

Claude.
 

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