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A highly desirable property of metals like gallium and indium is that they are able to wet glass.

Normally, as metals, they wouldn't be able to form an airtight seal when in contact with glass. But they are able to do so, and they can be used in applications where an airtight seal is required (e.g. vacuum gaskets).

That said, indium and gallium are somewhat expensive (at press time, around 700 USD/kg and 250 USD/kg, respectively). Industrial compounds that also have similar properties, such as Galinstan (even though the glass still needs a wetting with gallium oxide first), aren't much better.

What are some metal substances that are both cost-effective and able to wet glass with an airtight seal that can be used in industrial applications?

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My first thought was to use a small amount of chromium and then another metal (gold). This is how its done for electronics structures on glass. The chromium does react with the silicium-oxid and hence has strong bonding. I've done this only with layers of very small thickness (sub µm), and only via a PVD-technique.

But, as you can read on this Wikipedia page, it can be done in this way for glass-metal seals. For example, with chromium and stainless steel. As such, I think it is rather cost effective, at least if you compare it with pure indium and gallium.

If your application has temperature gradients, be aware of the potentially very different temperature coefficients.

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