Specialty Metal Films Co., LLC

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Solderable metal films on optical components

Metalized 16mm Infrared Windows

 Metalized 16mm Infrared Windows
    SMFCo is ITARS registered 

Metalized Optical Windows
Applying the perimeter solderable metal layers to optical windows is what we do.........  not all that we do, but almost all that we do.
It is certainly the lion's share of our business......not a sideline. 

The front end of the metalizing process involves applying a protective cover over the clear aperture.  The covers are usually made from Corning Microsheet glass.
We make the glass masking covers to the match the size specified on your drawing, assuming a machining tolerance of +/- .002"  We also have a large inventory of these covers on hand from which we can draw. These covers are reusable, so in most cases we will have the right size in stock to match your clear aperture. Placement accuracy (concentricity) of the masking cover on the optical face is typically .002" to .003" TIR.  
For the highest possible reliability of the metals system, it is best that the metals be deposited only onto the substrate material, and not overlap on top of the anti-reflection coating, but that is not always practical.  We can and do apply our metals on top of AR coatings, usually with no issues whatsoever.
There are basically two options when selecting the metals for your solder band, those being,
      a) Cr-Ni-Au, and
      b) Cr-Pt-Au,  
There are other choices, most certainly, but these two schemes are, by far, the most common.  Of these options, the Platinum scheme is the more reliable, if for no other reason than it having a virtually unlimited shelf life, whereas the Nickel scheme, normally, will have a shorter shelf life.  But the better reason for choosing Platinum over Ni lies in it's soldering characteristics.  Platinum is dissolved by the solder at a much slower rate than is Nickel, meaning that it will tolerate a longer dwell time in the liquidus phase of Sn rich solders before showing any sign of dewetting.  We have also found that we are able to reflow the Platinum scheme several times, if necessary, without compromising the joint.
Some of our Pt customers prefer not to have any gold top coat, as the gold can form brittle intermetallic compounds within the melt.  
Every project is always a little different. Please feel free to call or email us with the specifics of your application and we can help you make these decisions and get you a price quote very quickly.

We can typically can turn around your order in two to three weeks ARM.