Specialty Metal Films Co., LLC

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Solderable metal films on optical components

 Specialty Metal Films Co. is ITARS registered.
Frequently Asked Questions

Our windows require optical coatings on both sides.....do they go on before or after your metals?

We can do it either way, however it is more common for the metal solderband coatings to be applied after the optical coatings, mainly to ensure that the metals remain pristine.

Can you apply the metals directly over the optical coatings?

They can be, depending on the composition of the optical films, but a much more reliable hermetic seal will be made if the metals are deposited directly onto the substrate material.  The optical coating process normally requires a "tooling land area" around the perimeter of the window which will be free of the coatings, so this is rarely a problem. If the top layer of the optical stack is MgF2, SiO, or SiO2, then we can bond to these materials as well as we bond to the substrate material, however, if the top layer of the stack is one of the Zinc compounds, then we do not recommend applying metals over this material.  One way or another, we always do a test run, to be certain. 

We need the edges of our windows metalized, as well as the top surface perimeter......is this a problem?

Not at all, but you need to make us aware that this area is critical to your sealing process, as we need to take some special measures to make sure that you get good coating quality on the vertical edges of your windows.

Can we have our windows coated on three sides, top, bottom, and edge?

Yes, but this option should be considered carefully as it adds significantly to the cost of the metalizing process, as well as adding a LOT of extra handling.........more handling always means potential cosmetic damage to the optical coatings. 


How hot will our windows get during the metalizing process?

Not to exceed 75° C

What is the maximum temperature that these films will survive?

450-500°C, but we have a recent report from a customer who has taken them to brazing temperatures (800C+) without failure.......yes, that surprised us too! 




Solderable rim applied to germanium domes


Specialty Metal Films Co., LLC
1248 Highland Street
Holliston, MA 01746

Contact: Tom Killoren, tkilloren@specialtymetalfilms.com