by Looking In » Fri Oct 12, 2007 10:29 am
kumaran,
I have had in my first cells lots of the brown scum. As I was explaining in my earlier post it all comes down to the prep. No one want's to take the time to find out why? When most just want to put the plates in and create hydroxy.
They suffer tear downs, and will have to resand the plates again. Just more work.. IF the just look at the logic. What is that brown scum and what causes it? Iron.. Iron.. Iron.. Iron.. So How do we get rid of it?
Passivation it was posted Wed Nov 01, 2006
In lay terms, the passivation process removes "free iron" contamination left behind on the surface of the stainless steel from machining and fabricating. These contaminants are potential corrosion sites that result in premature corrosion and ultimately result in deterioration of the component if not removed. In addition, the passivation process facilitates the formation of a thin, transparent film that protects the stainless steel from selective oxidation (corrosion). So what is passivation? Is it cleaning? Is it a protective coating? It is a combination of both.
The three major variables that must be considered and controlled for the passivation process selection are time, temperature and concentration. Typical immersion times are between 20 min and two hours. Typical bath temperatures range between room temperature and 160F.
Rich (Looking In)
((((Is it really so difficult to tell a good action from a bad one? I think one usually knows right away or a moment afterward, in a flash of regret.)))) BOOM