The symbolization epoxy is initially anatase-based, which provides the
brilliant definition. However, this phase changes to rutile in the
presence of heat and then the crystals become almost like xenotine. Both
the rutile stage and xenotine have more of a pinkish tan or almost beige
color. So when heated, the anatase properties become rutile and thus the
color change. Also, the anatase is optically negative and rutile is
positive. This tends to accentuate the color change.  
This is very common, especially when rosin-based fluxes are in contact
with the symbolization, but I am not sure just why. I have seen it
happen many times, but it was not really a concern as the symbolization
was still very legible. It is still inert.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin Asbell
Sent: Thursday, September 08, 2005 11:38 AM
To: [log in to unmask]
Subject: [TN] Pink symbol ink...

We got a call from a customer expressing an interesting issue.



They ran product through their wave solder and the symbolization went
from white to pink.



I've never heard of this color change appearing, anyone out there have
an idea?



The symbol is Enthone 50-100R - white, the wave solder info I have is
Type R flux with a peak temperature of 215 C.



Appreciate any input, thanks.



Franklin

pI


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