I recommend Master Bond 11AOHT or EP21TDC. The 11AOHT has the lowest TCE
(10 in/in/°C x 10 to the -6). They are available in either gray or amber
color, however, I do not know as to how translucent. Please consult Dr.
Walter Brenner, Technical Director with Master Bond , Inc. 154 Hobart
Road Hackensack, N.J. 07601 (201) 343-8983. You may also consider one of
the Summers Optical Lens Bond Optical Cements. Their average TCE is
about 6X that of the Master Bond 11AOHT, but that may be a tolerable
value in exchange for clarity. Their contact data is: 321 Morris Road
Fort Washington, PA 19034 (800) 523-5874. Please follow up with your
solution.

Chris Taylor
Senior Printed Circuit Designer
LXE, Inc.
125 Technology Parkway
Norcross, GA 30092
voice: (770) 447-4224 X3242
fax: (770) 447-6928
e-mail: [log in to unmask]


>----------
>From:  Ron Hom[SMTP:[log in to unmask]]
>Sent:  Wednesday, February 18, 1998 10:44 PM
>To:    [log in to unmask]
>Subject:       [DC] bonding kovar to sapphire
>
>	
>        I am looking for an adhesive with the following properties:
>
>        1. Capable of bonding kovar to sapphire.
>        2. Hermetic seal. 
>        3. Thermal coefficient of expansion (TCE) of approximately 5.66
>x 10^-6 in/in /°C 
>            (0 to 100 °C range).    
>        4. Translucent.
>        5. Fast curing, with no outgassing.
>
>        I need to bond two sapphire windows to each side of a 2.5" kovar
>wheel. 
>        The kovar wheel has two gas filled chambers. One chamber is
>filled with carbon monoxide and the other with
>        nitrogen.
>
>        Since sapphire and kovar have similar thermal expansion
>coefficients (between 3.24 - 5.66 x 10^-6 in/in/°C), 
>        it would be ideal if the adhesive also had a low thermal
>coefficient of expansion.
>
>        The completed wheel assembly will be rotated at  1800 rpm under
>very little vibration. 
>
>        Below is a drawing of what I would like to build. Thank you in
>advance for your consideration.
> 
>        Ron Hom
>        Advanced Pollution Instrumentation, Inc.
>        6565 Nancy Ridge Dr.
>        San Diego, CA  92121-2251 
>
>        tel: (619) 642-7766
>        fax: (619) 657-9819
>        email: [log in to unmask]
>
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