Overview:
Passivation as referred to in this section will be in relation to Stainless Steel and mainly 316L as used in the
Pharmaceutical, Bio-Tech, Electronics and food industries.
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Passivation: |
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Passivation is the means of obtaining the electrochemical condition of "Passivity" through stabilization of
the "Passive Layer." This is generally accomplished through special chemical application(s). There are two alternatives that may be used:
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Passivity: |
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| Passivity is the state in which a stainless steel exhibits a very low corrosion rate. This is achieved by the formation and continuation of a viable "Passive Layer". |
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Passive Layer: |
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Authorities and experts tend to differ in their explanation of the Passive Layer. However it is generally agreed that it is a film which acts as a barrier to further corrosion. The Passive Layer is not a coating and in fact reacts with its environment. Therefore this layer is not of constant depth but is constantly depleated and replenished.
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Why is it needed? |
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Even a shiny clean looking 316L componant may have certain impurities impregnated into the surface. Some of these may be from the melt and others will have been added during Surface Finishing, Welding and Electropolishing and even from surface dusts.
Corrosive mediums such as WFI and Clean Steam accelerate the formation of corrosive products in a system when surfaces are not properly prepared.
These corrosive products are found as "rouge" in a system.
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What is Rouge ? |
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Put very simply "rouge" is your system actually corroding.
316L is approximatly 64%-67% Iron, given a chance 316L will revert back to Iron oxide.
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