SQLGuy

Jim,

What do the white bars/boxes next to the stainless steel alloys mean? Do these alloys act differently under different circumstances?

Thanks,
Paul

jon928se

Stainless can be active or passive - passive if the surface can develop a passivating oxide layer which is generally good.

In the absence of oxygen and in the presence of the right electrolyte even stainless and stainless (yes I did say stainless and stainless) of differing alloys can cause corrosion of one of them at a rate that makes mild steel appear as long lasting as gold.

jon928se

The other thing to consider is the relative surface areas of the two metals.

If you have two equal surface areas of two metals one of which is only slightly cathodic relative to the other nothing much will happen.

However if you have a large surface area cathode in contact with a small surface area of something slightly less cathodic corrosion can be quite rapid.

depami

Years ago I worked on X-ray film processors. I saw more than one stainless steel tank (don’t remember if it was developer or fixer tank) where a paper clip ate right through the bottom.

bradartigue

Which is what happening to my body the 125 times a year I go through our nation's airports.

I am the tank.